Re: James Randi gets clarified on audio biz
out...@city-net.com
methodology is generic and designed to offer the best chance for the
claimant to demonstrate claims in a transparent manner. His methods to
draw attention are as you describe, old showmen don't die...
>> Your reservations about him,
>> the prize, and his approach are perfect for turning the tables;
>
>I don't think he turns the tables - I *do* respect him for what his
>purported goals are - I just don't like the sensational methods.
B&D
:-)
On 9/20/04 8:04 PM, in article cinr5...@news2.newsguy.com,
Nousaine
What I don't understand is why any proponent isn't rushing to collect the
prize. At the very least they all know the tricks of the trade; and if they
"really can" hear these differences why can't they just DO it?
Some seem to be implying that sensitive people can be tricked into "un-hearing"
real differences. That's NOT what I get by reading the manufacturers
literature.
If wire/amp/bit/tweak sound IS audible why are people arguing about the
circumstances? It's simply another case of "I've got the fastest car in the
valley ..... but I can't prove it if you are going to actually race the cars or
use a stopwatch."
S888Wheel
>Date: 9/20/2004 8:36 PM Pacific Standard Time
>Message-id: <cio7k...@news3.newsguy.com>
>
>B&D br...@ix.netcom.com wrote:
>
>
>
>>
>>Yup - and as a stage magician, Randi has more than a little of that helping!
>>:-)
>>
>>On 9/20/04 8:04 PM, in article cinr5...@news2.newsguy.com,
>>"out...@city-net.com" <out...@city-net.com> wrote:
>>
>>> Turning tables was an advantage offered the magazine, Randi's test
>>> methodology is generic and designed to offer the best chance for the
>>> claimant to demonstrate claims in a transparent manner. His methods to
>>> draw attention are as you describe, old showmen don't die...
>>>
>>>
>>>>> Your reservations about him,
>>>>> the prize, and his approach are perfect for turning the tables;
>>>>
>>>> I don't think he turns the tables - I *do* respect him for what his
>>>> purported goals are - I just don't like the sensational methods.
>
>What I don't understand is why any proponent isn't rushing to collect the
>prize. At the very least they all know the tricks of the trade; and if they
>"really can" hear these differences why can't they just DO it?
Simple. There is no chance of collecting the money. No one is claiming their
product is is paranormal. If per chance any of the products Randi is targeting
were to make an audible difference there wold be a nonparanormal explination
for that difference. Why bother?
>
>Some seem to be implying that sensitive people can be tricked into
>"un-hearing"
>real differences. That's NOT what I get by reading the manufacturers
>literature.
>
>If wire/amp/bit/tweak sound IS audible why are people arguing about the
>circumstances? It's simply another case of "I've got the fastest car in the
>valley ..... but I can't prove it if you are going to actually race the cars
>or
>use a stopwatch."
>
If you can talk Randi into expanding the challenge to amplification let me
know. I doubt he would do it.
out...@city-net.com
me
know. I doubt he would do it."
I wouldn't be so sure of that, if he isn't, there is another who has 10
thousand dollars motivation for the same goal for amps. I'm told many have
tried and he still has it.
Lasse
>
> Simple. There is no chance of collecting the money. No one is claiming
> their product is is paranormal. If per chance any of the products Randi
> is targeting were to make an audible difference there wold be a
> nonparanormal explination for that difference. Why bother?
Paranormal is not a clearly defined word. There seem to be no scientific
evidence Shakti Stones or Tice Clock affecting sound. So, sound of these
products could be defined paranormal. James Randi has personally stated
that anyone, who can hear if Shakti Stones are used or not can claim the
prize:
"Folks, all you have to do to win a million dollars, is to be able
to tell when the Shakti Stones are in use, or are NOT in use!"
http://db.audioasylum.com/cgi/m.mpl?forum=general&n=341741
His other posts to Audio Asylum: http://tinyurl.com/4bs5s
> If you can talk Randi into expanding the challenge to amplification let me
> know. I doubt he would do it.
Oh dear? You are wealthy man, aren't you? Because there is already a
$10000 amp challenge by Richard Clark. For me even $10000 would be
good money for one day effort. http://tinyurl.com/6s92v
Lasse Ukkonen
S888Wheel
>Date: 9/21/2004 8:01 PM Pacific Standard Time
>Message-id: <ciqpt...@news1.newsguy.com>
I doubt very much that the bet is that straight forward. If some one wants to
test my assertion that my Audio Research SP 10 and D-115 sound different than
my old Yamaha reciever with Martin Logan CLs speakers and pay a million dollars
or even ten thousand if I hear a difference under blind conditions I'll happily
invite them over and find that old reciever.
Stewart Pinkerton
Since you quote me in that post, I should point out that I am a
contributor to the $5,000 'cable challenge' pool which has indeed been
extended to amplifiers (and has stood unchallenged for more than five
years now), and I have a standing offer of £1,000 (I'm not as rich as
Randi!) to anyone in the UK who can 'hear' cables or amplifiers under
level-matched blind conditions.
--
Stewart Pinkerton | Music is Art - Audio is Engineering
Steven Sullivan
> >From: nous...@aol.com (Nousaine)
> >Date: 9/20/2004 8:36 PM Pacific Standard Time
> >Message-id: <cio7k...@news3.newsguy.com>
> >
> >B&D br...@ix.netcom.com wrote:
> >
> >
> >
> >>
> >>Yup - and as a stage magician, Randi has more than a little of that helping!
> >>:-)
> >>
> >>On 9/20/04 8:04 PM, in article cinr5...@news2.newsguy.com,
> >>"out...@city-net.com" <out...@city-net.com> wrote:
> >>
> >>> Turning tables was an advantage offered the magazine, Randi's test
> >>> methodology is generic and designed to offer the best chance for the
> >>> claimant to demonstrate claims in a transparent manner. His methods to
> >>> draw attention are as you describe, old showmen don't die...
> >>>
> >>>
> >>>>> Your reservations about him,
> >>>>> the prize, and his approach are perfect for turning the tables;
> >>>>
> >>>> I don't think he turns the tables - I *do* respect him for what his
> >>>> purported goals are - I just don't like the sensational methods.
> >
> >What I don't understand is why any proponent isn't rushing to collect the
> >prize. At the very least they all know the tricks of the trade; and if they
> >"really can" hear these differences why can't they just DO it?
> Simple. There is no chance of collecting the money. No one is claiming their
> product is is paranormal. If per chance any of the products Randi is targeting
> were to make an audible difference there wold be a nonparanormal explination
> for that difference. Why bother?
This objection was soundly refuted the *first* time you posted it in
this thread, Scott. Why do you repeat it?
Lest you be tempted to post it a third time, and so there can be no
question what Randi ahs and has not offered, here is Mr. Randi's offer,
as it relates to audio quackery, verbatim from his site. Please
note his explicit references to the prize, and to 'eligible material',
and to Shakti Stones:
//
THE JREF MILLION IS SURELY WON
Reader Phil Ray, a medical research analyst in Lexington, Kentucky,
tells us about some more "high-end" audio flummery he's discovered:
'Your mention of the "Tice clock" and other audiophile snake-oil
devices
got me digging around on the internet for more. I ran across a couple
of good sites, but the one that takes the cake is
www.belt.demon.co.uk/index.html.
Apparently, according to this site, you can improve all kinds of audio
devices or recording media performance just by writing "O.K." on them ?
or a piece of tape stuck on them ? with a "specially treated" marker
pen. Writing "NO" makes things sound much worse. There is much more
available from "P.W.B. Electronics" as well, that could be eligible for
the JREF Prize.'
This is the fabulous "Red 'x' Pen" that you can have for a mere US$87!
And yes, there sure was more eligible material. For example, I found a
glowing review of some mystical P.W.B. sticky foil on that site. It
claimed that tiny little scraps of it could improve a wide spectrum of
our daily lives:
These shiny little devil-strips are supposed to work their effects just
by placing them on pretty much anything in the system ? or the house,
for that matter. Suggested application included batteries in remote
controls, clocks, and calculators, mains plugs on amplifiers, CD
players, tuners, televisions, computers, even fax machines, light
switches, transformers, auxiliary power sources, central-heating
radiators or air-conditioning units, even equipment casings, lids, and
LED displays.
Here's an example of how versatile the wondrous P.W.B. Electronics
Electret Foil is, as explained by Mrs. May Belt, one of the promoters,
retailers, and producers of P.W.B. products. They had been
experimenting with improving the sound of their system by applying a
scrap of this foil to a CD:
'During one set of listening experiments, we had a short coffee break.
In the listening room was a small wooden table which had had something
spilt on it, causing a nasty stain. Peter decided to treat this stain
and applied a chemical to it. No success ? the stain was just as bad.
Peter shrugged his shoulders and said, "Oh well, we will just have to
live with the stain, at least I have tried to remove it."
After the short coffee break we returned to the listening tests. The
sound was dreadful, it was absolutely appalling! Peter tried everything
he knew but could not get the previous "good" sound back. He knew that
the only thing he had done in the past half-hour was to apply a
chemical to the stain on the small table. He took the table out of the
room and listened again. The "good" sound was back! With the table
returned to the room, the sound was dreadful again. Peter remarked,
"There is no way we can carry on with our listening tests with that
table in the room," so the table was banished to the garage.
We had no explanation for what had happened but we remembered this
incident because it was so surprising and startling. It was a few
months later that I happened to be reading an article ? an article on
plants! In the middle of this article it stated "and when the (???)
plant is under stress, it produces the chemical ????" ? this was the
chemical we had applied to the small table!!! I read this article out
to Peter and we looked at each other. Here was the chemical we had used
being described as a "stress chemical." Peter then began to reason out,
"I wonder if it was us (human beings) who were sensing this "stress"
chemical and going under tension ? and this was the reason why the
"sound" was perceived as "dreadful."'
I'd find it difficult to comment here, especially since my eyes are
full of tears from laughing. Are these simply raving loonies, or is it
a very unfunny joke? I wish it were a joke.
I found a glowing review of this magic foil at Greg Weaver's April 1999
Rainbow Foil review and immediately wrote him at gr...@soundstage.com:
Mr. Weaver: I've been forwarded some comments you made on the "P.W.B.
Electronics Electret Foil" and wished to inform you that if you are
able to repeat your experiments ? double-blind ? you would certainly
win the JREF million-dollar prize as described at
www.randi.org/research/index.html and
www.randi.org/research/challenge.html.
Are you interested?
I'm not going to expect a response, of course, but I'll inform you if I
get one. Phil has more:
I looked up "Shakti Stones," too, at
http://www.shakti-innovations.com/index.html. They have the added
benefit of having an "East Indian" name. They not only make your stereo
sound better, but another version improves engine performance and
increases horsepower in your car!
I'm so glad to live in the 21st Century ? an era when wonders never
cease!
The Shakti Stones, fortunately, don't even have to be connected to
your sound system, but can be simply placed nearby, to produce
wonderful improvements! The instructions simply say:
Use of the Stones could not be simpler, simply place them near power
supplies, components or CD/DVD/SACD players, the nearer the transformer
the better.
Incredible! One reviewer, "expert" Dick Clark of Audio Journal, ended
up with eleven of these stones ($2,530 worth!) placed all over his
system, and he raves about the improvements! Phil, I'm an
equal-opportunity kind of guy, so I sent this inquiry ? via both e-mail
and postal mail ? to a Mr. Mintz, who had also very enthusiastically
endorsed his Shakti stones:
I understand that you have found wonderful results from the use of
"Shakti Stones" in conjunction with your sound system! To amplify your
delight, I inform you that if you can successfully perform a
double-blind test of these stones, as you have described, you can win
the million-dollar prize offered by this Foundation. See details at
www.randi.org/research/index.html and
www.randi.org/research/challenge.html.
I await your response with great interest.
Now, Weaver and Mintz may or may not respond. I'll keep you updated on
the matter. Consider: if they do not respond, why did they choose that
option? Several possibilities present themselves:
Maybe they now find that they were self-deceived.
Perhaps they are afraid to test their firmly-stated convictions on the
matter.
They might be independently wealthy and thus disinterested in the
million-dollar prize.
It's even possible that these people are fictional inventions of the
vendors of these hi-tech advances in science.
There must be some reason. I am sending out 11 letters to audio
reviewers who endorsed this thing, making the same offer. "
--
-S
Your a boring little troll. How does it feel? Go blow your bad breath elsewhere.
out...@city-net.com
"I doubt very much that the bet is that straight forward. If some one
wants to test my assertion that my Audio Research SP 10 and D-115
sound different than my old Yamaha reciever with Martin Logan CLs
speakers and pay a million dollars or even ten thousand if I hear a
difference under blind conditions I'll happily invite them over and
find that old reciever."
Richard Clark is the person and his prize was the topic of at least one
thread within the past year here. As I recall without looking at the
archives, he wants level matching, no clipping of either amp and other
such common sense things which might give an amp away and don't relate to
the basic question. He also had some stipulations to guard against
someone using a ringer amp whose freq or other response had been modified
to make it obvious, in which case he proposed using an eq on his amp to
match the output of the other amp. Another person who posts here has also
had considerable experience in the amp testing area and has yet to fine
someone who can pass the test beyond a level similar to guessing, but no
doubt he can speak for himself. An older yamaha and then current nelsom
pass labs amp were the subject of one such test, no luck; just to provide
a reference for your intrest using an amp of that brand.
Nousaine
wrote:
I'll happily pay you a hundred dollars to 'prove ' what you claim to hear.
S888Wheel
>Date: 9/23/2004 5:06 PM Pacific Standard Time
>Message-id: <civoe...@news1.newsguy.com>
Why not repeat your own amp tests that wrought positive results and collect the
money?
S888Wheel
>Date: 9/23/2004 8:22 PM Pacific Standard Time
>Message-id: <cj03...@news1.newsguy.com>
Nousaine
All you have to do is show that you can hear those differences under blind
conditions.
Stewart Pinkerton
>Why not repeat your own amp tests that wrought positive results and collect the
>money?
Interesting that no one else has picked that one up. It would indeed
be interesting to revisit that test series, with the rather more
rigorous pre-conditions of the full challenge.
S888Wheel
>Date: 9/24/2004 12:03 PM Pacific Standard Time
>Message-id: <cj1r1...@news3.newsguy.com>
proof would you want?
Lasse
>
> Since you quote me in that post, I should point out that I am a
> contributor to the $5,000 'cable challenge' pool which has indeed been
> extended to amplifiers (and has stood unchallenged for more than five
> years now), and I have a standing offer of £1,000 (I'm not as rich as
> Randi!) to anyone in the UK who can 'hear' cables or amplifiers under
> level-matched blind conditions.
I hadn't heard of that extension of cable challenge, interesting. Maybe
a short summary would be in order. Known audio challenges:
$1.000.000 Shakti Stones, Tice Clock, etc. (James Randi)
$10.000 Amplifiers (Richard Clark)
$5.000 Cables and amplifiers (RAHE pool)
~$1,800 Cables (Stewart Pinkerton)
Also, if Randi offers money for hearing the effect of Shakti Stones,
then we can assume that other sceptic organisations might do the same:
~$57.000 Australian sceptics challenge for extraordinary powers
~$14.000 Australian sceptics spotter fee: You only have to _find_ a
person who has extraordinary powers, ie. can hear Shakti Stones!
~$10.000 Finnish Skepsis challenge
I might have missed other challenges but even these challenges could
pay off ~$1.100.000 for that person who hears Shakti Stones, amps and
cables. I must say that situation is now extremely interesting since
Randi is involved with his million.
Lasse Ukkonen
Stewart Pinkerton
OK, I'll bite. I hereby formally offer £10,000 to anyone who can
differentiate two cables under the usual level-matched DBT conditions.
Furthermore, I'll make it £100,000 as a bet.
Nousaine
So you say. Others have claimed the same. Steve Zipser claimed he regularly
aced blind listening tests regarding amplifiers but when asked to do so under
verifiable conditions was unable to do so. Pardon me if I remain skeptical.
Howard Ferstler
I find it rewarding to discover just what was probably
involved when you did your amplifier comparisons. Now I
realize why you think you can hear differences with amps.
Prior to the above-noted comparison being done, it would be
a good idea to bench check those Audio Research units to
make sure that (because of their probably high output
impedances) they are not delivering a non-flat signal to
your speakers, or to any other speakers they might be called
upon to power as well.
Actually, with electrostatic systems, it is possible that
both the Yamaha and Audio Research amps are not performing
to audibly smooth perfection. The Yamaha might have problems
with the reactive load and be distorting because of that,
and the Audio Research jobs might have frequency-response
irregularities that involve their output impedances in
relation to the input impedance of the speakers.
Few "objectivists" would say that all amps sound the same
when driving oddball speaker loads, and few would say that
amps with high output impedances were flat responding into
any speaker load. However, they would say that into
reasonably normal loads decently designed amps should sound
the same up to clipping levels.
Howard Ferstler
Nousaine
I'd make the conditions a little more specific. I've heard a demonstration at
an AES Convention where it was demonstrated that one could "hear" 100-feet of
30 ga wire wrap wire.
Nousaine
Just out of interest what is the Finnish Skepsis Challenge? Why not the Sisu
challenge :->
Stewart Pinkerton
>Stewart Pinkerton pat...@dircon.co.uk wrote:
>>OK, I'll bite. I hereby formally offer Ł10,000 to anyone who can
>>differentiate two cables under the usual level-matched DBT conditions.
>>Furthermore, I'll make it Ł100,000 as a bet.
>I'd make the conditions a little more specific. I've heard a demonstration at
>an AES Convention where it was demonstrated that one could "hear" 100-feet of
>30 ga wire wrap wire.
Sure, but level matching at 100, 1,000 and 10,000 Hz to +/- 0.1dB (the
standard pre-conditions) should remove the 'ringers' and leave only
the numerology and unobtainium contenders.
Tat Chan
> OK, I'll bite. I hereby formally offer Ł10,000 to anyone who can
> differentiate two cables under the usual level-matched DBT conditions.
> Furthermore, I'll make it Ł100,000 as a bet.
You are probably posting this to the wrong NG.
I think most people who believe in cable sound, CD players/amps sounding
different, mains filters, digital stair steps, "which
resolution/sampling frequency best approaches analogue", CD
de-magnetizers, etc read Audio Asylum, AudioEnz and EchoLoft (to name
some Web forums I know of) instead of UseNet.
I assume "usual level-matched DBT conditions" include
- testing the frequency response of the provided cables (fed via a
signal generator and read on a CRO?) at selected frequencies
- playback via the system of the challenger's choice
- music selected by the challenger
would the challenger have to provide 2 separate cables, or will there be
a "reference" cable?
(I know, I should search the UseNet archives but ...)
S888Wheel
>Date: 9/26/2004 3:19 PM Pacific Standard Time
>Message-id: <cj7f8...@news2.newsguy.com>
your offer or are you just posturing? I cannot offer proof without knowing
precisely what you want in the way of it.
S888Wheel
>Date: 9/26/2004 3:23 PM Pacific Standard Time
>Message-id: <cj7fg...@news2.newsguy.com>
My assertion was and is that I heard a difference. One that I found meaningful.
I did not ascribe any explination for it just that I heard it. If Randi wants
to pay me to a million dollars to prove it or if some one else wants to pay me
10,000 dollars to prove it I will happily repeat my comparisons.
Lasse
>
> Just out of interest what is the Finnish Skepsis Challenge? Why not the Sisu
> challenge :->
It's roughly the same as the Randi challenge. 10.000 euros for anyone who
can create a paranormal phenomenon in controlled conditions. Paranormal
is defined as any phenomenon that contradicts prevailing scientific view.
If Randi says that hearing Shakti Stones can be interpreted as paranormal,
then other sceptic organisations might do the same.
http://www.skepsis.fi/eng/ (Skepsis introduction in English)
http://www.skepsis.fi/haaste/saannot.html (Rules of the challenge in Finnish)
Lasse Ukkonen
Steven Sullivan
> Stewart Pinkerton wrote:
> > OK, I'll bite. I hereby formally offer ?10,000 to anyone who can
> > differentiate two cables under the usual level-matched DBT conditions.
> > Furthermore, I'll make it ?100,000 as a bet.
> You are probably posting this to the wrong NG.
> I think most people who believe in cable sound, CD players/amps sounding
> different, mains filters, digital stair steps, "which
> resolution/sampling frequency best approaches analogue", CD
> de-magnetizers, etc read Audio Asylum, AudioEnz and EchoLoft (to name
> some Web forums I know of) instead of UseNet.
Not to mention Stereophile and The Absolute Sound.
I wonder what would happen if the 'challenge' were to be
offered in the letter columns of *those* august journals?
Stewart Pinkerton
wrote:
>Stewart Pinkerton wrote:
>
>> OK, I'll bite. I hereby formally offer Ł10,000 to anyone who can
>> differentiate two cables under the usual level-matched DBT conditions.
>> Furthermore, I'll make it Ł100,000 as a bet.
>
>You are probably posting this to the wrong NG.
>
>I think most people who believe in cable sound, CD players/amps sounding
>different, mains filters, digital stair steps, "which
>resolution/sampling frequency best approaches analogue", CD
>de-magnetizers, etc read Audio Asylum, AudioEnz and EchoLoft (to name
>some Web forums I know of) instead of UseNet.
>
>I assume "usual level-matched DBT conditions" include
>- testing the frequency response of the provided cables (fed via a
>signal generator and read on a CRO?) at selected frequencies
Yes, although I use a Fluke multimeter rather than a 'scope, and
usually feed from a test CD, although I do have a genny.
>- playback via the system of the challenger's choice
Yes
>- music selected by the challenger
Yes
>would the challenger have to provide 2 separate cables, or will there be
>a "reference" cable?
Either or
>(I know, I should search the UseNet archives but ...)
Yes, you should! :-)
Nousaine
Interesting. Thanks. I find that I can perform lots of paranormal activity in
my sauna. The original Finnish spelling of my last name is Nousiainen.
B&D
Pinkerton" <pat...@dircon.co.uk> wrote:
Sure - and it would remove the source of the differences as well. If
someone is trying to drive Martin Logan speakers that have a 1 Ohm impedance
(mostly reactive) at 20kHz - and one amp can drive it, and another can't
(either folds back, oscillates, rolls off the upper frequencies or whatever)
- there will be a noticeable difference - and the "challenge" will be
useless to someone in that situation that says that one amp is better than
another - because it is!
While I didn't have a problem exactly like it, I had a HT amp that wasn't
capable of driving my speakers - and an amp with more power did the trick -
and it sounds much better. I was able to "hear" the difference easily - but
I think the amplifiers themselves probably didn't have an inherent "sound"
though such a challenge that said that with no further education about
matching amp drive to speakers and other nuances of good system construction
is doing as big a disservice as the superstition surrounding these pieces of
equipment!!
B&D
<s888...@aol.com> wrote:
>> Few "objectivists" would say that all amps sound the same
>> when driving oddball speaker loads, and few would say that
>> amps with high output impedances were flat responding into
>> any speaker load. However, they would say that into
>> reasonably normal loads decently designed amps should sound
>> the same up to clipping levels.
>>
>
> My assertion was and is that I heard a difference. One that I found
> meaningful.
> I did not ascribe any explination for it just that I heard it. If Randi wants
> to pay me to a million dollars to prove it or if some one else wants to pay me
> 10,000 dollars to prove it I will happily repeat my comparisons.
I think the point that is being missed is simple - by removing sources of
differences (the appropriate amp to the appropriate speaker) the challenge
is both 100% correct, and 100% unhelpful and possibly will lead people into
incorrectly believing that any old amp is good for ANY speaker of any load.
Nousaine
OK the conditions are: level matched at 100,1000 and 10,000 Hz. Blind
comparisons either cable swaps or ABX switched. 10 or more trials (9 of 10, 12
of 16, 15 of 20 correct to show proof.) You pick the programs. No time limits.
If you can identify the amplifiers under blind conditions I'll pay you $100. If
you fail you re-imburse half my travel cost. Alternately you can forward your
system to me. In that case If you can prove your case I'll pay for your travel
and shipping plus the $100.
Tat Chan
> Tat Chan <le_kin...@hotmail.com> wrote:
>
>>I think most people who believe in cable sound, CD players/amps sounding
>>different, mains filters, digital stair steps, "which
>>resolution/sampling frequency best approaches analogue", CD
>>de-magnetizers, etc read Audio Asylum, AudioEnz and EchoLoft (to name
>>some Web forums I know of) instead of UseNet.
>
>
> Not to mention Stereophile and The Absolute Sound.
>
> I wonder what would happen if the 'challenge' were to be
> offered in the letter columns of *those* august journals?
>
An instant A-B comparison will probably be dismissed ... expect the
usual excuses like
"one has to listen to (or live with) the equipment for an extended
period of time to be able to make a better comparison. Various details
that were masked before hand can only be unveiled after a period of
time. Certain equipment will be less fatiguing to listen to for extended
periods of time. By making the comparison blind you will be putting
pressure on the listener".
Something like that anyway.
Bob Marcus
>
> I think the point that is being missed is simple - by removing sources of
> differences (the appropriate amp to the appropriate speaker) the challenge
> is both 100% correct, and 100% unhelpful and possibly will lead people into
> incorrectly believing that any old amp is good for ANY speaker of any load.
IOW, we shouldn't tell people the truth because they might
misinterpret it.
As for unhelpful, that assumes that all audiophiles are as smart as
you. They aren't. The great unwashed who populate the Asylum and
Audiogon and read TAS like it's the Kamasutra do not see this as a
problem of finding an appropriate amp to drive a particular load. To
them, the challenge is to find an amp with sonic attributes that
complement the sonic attributes of their speakers, wall outlets, and
everything in between.
The challenge isn't aimed at engineers like you who know which
properties of an amplifier are important in driving a particular load.
It's aimed at the non-technical audiophiles who are sure that their
years of experience as a "listener" allow them to hear subtleties in
each component that engineers cannot measure and are too narrow-minded
even to admit the existence of. For them, taking such a challenge
would be most enlightening--which is why they'll never do it.
bob
Bob Marcus
>
> OK the conditions are: level matched at 100,1000 and 10,000 Hz. Blind
> comparisons either cable swaps or ABX switched. 10 or more trials (9 of 10, 12
> of 16, 15 of 20 correct to show proof.) You pick the programs. No time limits.
I think you left out the clipping condition, though Scott's been
reading this board long enough to know exactly what the conditions
are.
bob
Stewart Pinkerton
Please note that this is a *cable* challenge, although your pint is of
course quite correct, hence the pre-qualifier that amps are not driven
into clipping. That's one reason I hang onto my Krell - I *know* that
it doesn't care if it's driving a rusty nail!
S888Wheel
>Date: 9/27/2004 9:00 PM Pacific Standard Time
>Message-id: <cjanl...@news4.newsguy.com>
get another Yamaha reciever like the one I had. That doesn't include the time
involved in tracking one down. I'll happily accept level matching at one
frequency but if you need to use an equalizer to match at several frequencies
you will no longer be testing my assertion that I heard a difference (no
equalizers were used in my comparisons). Travel expenses? So a condition of
this 100 dollar challenge is that you take a 500 dollar trip? C'mon. As for the
number of correct scores needed for a positive, I think the standard 95%
certainty should apply. Frankly I'd rather take the 10,000 dollar challenge
or...if some one can coax Randi into extending the million dollar challenge...
But let's face it, niether will challenge my assertion without fiddling with
the sound of the reciever. So, if some one really doubts I heard a difference
the challenge should simply be level matched (at one frequency) and double
blind with scientific standards for a positive. OTOH if you are ever in town
and have an old Yamaha reciever from their rack systems sold in the mid
eighties drop me an Email.
Stewart Pinkerton
No one has ever suggested any such thing - and such basic load-driving
incapacity is *never* the source of claims regarding amplifier sound.
Steven Sullivan
> > Tat Chan <le_kin...@hotmail.com> wrote:
> >
> Something like that anyway.
Probably, but quick switching and short audition times are not
requirements of bias-controlled comparisons...they're optimizations
that are used to *improve* performance of A-B comparison.
If 'audiophiles' want to forego them, they're free to.
Mike Kozlowski
Stewart Pinkerton <pat...@dircon.co.uk> wrote:
>No one has ever suggested any such thing - and such basic load-driving
>incapacity is *never* the source of claims regarding amplifier sound.
Maybe, but it's sometimes (often?) the source of purchasing. I
upgraded my amp from a (35wpc) NAD 314 to a (200-something wpc)
Parasound HCA-1500 pretty much entirely because I wanted to make sure
I got something that could drive whatever speakers I ended up buying.
(Also because it looked nicer, but shh, aesthetics are a "WAF"
consideration; people who are interested in music are obviously
uninterested in all forms of beauty and elegance.)
Talk about how all quality amps sound basically the same have the
implication that this was a totally lame and stupid move, and there'd
be no problem at all driving a pair of Martin Logan speakers off that
NAD, never be able to tell a difference. (Note: This may actually be
true, but am I going to take the chance of blowing a tweeter because I
can't do amplifer power to decibel level conversions when taking into
account speaker resistance and sensitivity levels? I am not.)
I'm pretty sure you're talking to people who buy Krell or Linn or
whatever the hell the big expensive amps are; but since you're often
following on cable conversations, which explicitly state that anything
more than Radio Shack 12 gauge is a waste of money, the effect of your
anti-amp-difference talk is to make it sound like a $299 Sony receiver
should be good enough for anyone.
--
Mike Kozlowski
http://www.klio.org/mlk/
Nousaine
>On 28 Sep 2004 00:45:15 GMT, B&D <br...@ix.netcom.com> wrote:
>
>>On 9/27/04 9:55 AM, in article cj963...@news1.newsguy.com, "Stewart
>>Pinkerton" <pat...@dircon.co.uk> wrote:
>>
>>> On 27 Sep 2004 03:21:59 GMT, nous...@aol.com (Nousaine) wrote:
>>>
>>>> Stewart Pinkerton pat...@dircon.co.uk wrote:
>>>
>>>>> OK, I'll bite. I hereby formally offer £10,000 to anyone who can
>>>>> differentiate two cables under the usual level-matched DBT conditions.
>>>>> Furthermore, I'll make it £100,000 as a bet.
No fair pirating my Rusty-Nail challenge. But quite frankly level matching
fully satisfies the 'clipping' issue in all but the most extreme case. In the
SMWTMS experiments experimenters had to compare a 10-watt tube amplifier vs a
400-watt solid state to get a "positive sound difference result." Even in that
case the output impedance may have influenced the results disqualifying them at
3-point level matching.
It's a good point but clipping is often over-stated as a condition, in my
opinion.
Nousaine
So your challenge is posited on someone else producing the "product" you don't
own?
Not straight-up? Nowhere in your original offer was it mentioned that you no
longer have the product you said had a different sound.
I'll happily accept level matching at one
>frequency but if you need to use an equalizer to match at several frequencies
>you will no longer be testing my assertion that I heard a difference (no
>equalizers were used in my comparisons).
OK how about full band pink noise? But even so IF I could duplicate the "sound"
of your device with a garden variety equalizer what does that say about your
prefered amplifier?
Travel expenses? So a condition of
>this 100 dollar challenge is that you take a 500 dollar trip? C'mon.
Not a problem. All you have to do is prove your case and there is no cost to
you. And you get your hundred bucks.
As for
>the
>number of correct scores needed for a positive, I think the standard 95%
>certainty should apply.
Those are the scores I posted. 95% which are 9 of 10; 12 of 16; 15 of 20.
2-tailed.
Frankly I'd rather take the 10,000 dollar challenge
>or...if some one can coax Randi into extending the million dollar
>challenge...
So get to it. You've already admitted that you no longer have access to the
device you claimed sounded 'different.'
"Frankly" I'd say you aren't interested in showing that you can 'hear'
amplifiers.
>But let's face it, niether will challenge my assertion without fiddling with
>the sound of the reciever. So, if some one really doubts I heard a difference
>the challenge should simply be level matched (at one frequency) and double
>blind with scientific standards for a positive.
OK; but how are you going to prove your claims with a device you no longer
have? This is the nexus of the high-end argument; just come over here AND I'll
show you that I can "hear" the differences between these 2 amplifiers.
Then we find that you no longer have one of them. Then we are limited to level
match frequencies. Then NO equalizers are allowed (even IF they are ONLY
inserted in the comparative unit signal chain) and one is left to wonder why
the elongation of the signal path with an equalizer wouldn't necessarily REDUCE
the transparency of the original signal chain and be immediately recognizable
by an experienced high-end listener.
OTOH if you are ever in town
>and have an old Yamaha reciever from their rack systems sold in the mid
>eighties drop me an Email.
So this is your response? So you can't prove your original case because you no
longer have the device you were basing the challenge on? That I have to supply
both the device and spend $300 on a plane ticket plus bringing all my own
equipment; and then if you 'fail' I'm left with all the expense of the
experiment.
I've taken that challenge before. Do you wnat to know what happens? I've
traveled to Maine at my own expense on a challenge from a wire company that if
I 'came' to their facility they'd "show me" differences.
When I got there (arrival announced weeks in advance) they refused to conduct
the experiment claiming they never said they'd do so (even thought the
challenge had been confirmed in letter-form.)
On another occasion I paid my own expenses to proctor a blind experiment on
power amplifiers between an audiophile and a store owner in Florida. The owner
was unable to prove he was able to differentiate his $12k monoblocks from a
used Yamaha integrated amplifier under different conditions (switched, cable
swaps) using his personal reference systems in his reference room.
So what next? This was your challenge. You've accused me of being disengenous
my old Yamaha reciever with Martin Logan CLs speakers and pay a
>>million
>>>>>>>>>dollars
>>>>>>>>>or even ten thousand if I hear a difference under blind conditions
>>I'll
>>>>>>>>>happily
>>>>>>>>>invite them over and find that old reciever.
so exactly what is genuine about your challenge? You now say that you don't
even still have it. How can you make a challenge so transparent that it's
remotely likely that you'll ever find a challenger?
Stewart Pinkerton
>In article <cjct1...@news1.newsguy.com>,
>Stewart Pinkerton <pat...@dircon.co.uk> wrote:
>
>>No one has ever suggested any such thing - and such basic load-driving
>>incapacity is *never* the source of claims regarding amplifier sound.
>
>Maybe, but it's sometimes (often?) the source of purchasing.
As it should be.
> I
>upgraded my amp from a (35wpc) NAD 314 to a (200-something wpc)
>Parasound HCA-1500 pretty much entirely because I wanted to make sure
>I got something that could drive whatever speakers I ended up buying.
>(Also because it looked nicer, but shh, aesthetics are a "WAF"
>consideration; people who are interested in music are obviously
>uninterested in all forms of beauty and elegance.)
>
>Talk about how all quality amps sound basically the same
Note that the qualifier 'below clipping' is invariably used when this
statement is made. Hence, an appropriate power output for your
requirements is a given. No one has ever suggested that an original
10-watt Linsley-Hood amp is ideal for driving ATC SCM 10s!
> have the
>implication that this was a totally lame and stupid move, and there'd
>be no problem at all driving a pair of Martin Logan speakers off that
>NAD, never be able to tell a difference. (Note: This may actually be
>true, but am I going to take the chance of blowing a tweeter because I
>can't do amplifer power to decibel level conversions when taking into
>account speaker resistance and sensitivity levels? I am not.)
Lucky then that no one has ever suggested that this would be the case.
>I'm pretty sure you're talking to people who buy Krell or Linn or
>whatever the hell the big expensive amps are; but since you're often
>following on cable conversations, which explicitly state that anything
>more than Radio Shack 12 gauge is a waste of money,
That certainly *is* correct for 99.999% of domestic audio systems.
> the effect of your
>anti-amp-difference talk is to make it sound like a $299 Sony receiver
>should be good enough for anyone.
Not if you actually *read* what's written, it's not. Is a Krell FPB300
better sounding than a Yamaha P4500? Possibly, probably not, but
either is capable of driving pretty much any speaker you're likely to
own. Oh, and the Krell costs $9,000, the Yamaha $700.........
Buster Mudd
> In
> the
> SMWTMS experiments experimenters had to compare a 10-watt tube amplifier
> vs a
> 400-watt solid state to get a "positive sound difference result." Even in
> that
> case the output impedance may have influenced the results disqualifying t
> hem at
> 3-point level matching.
>
> It's a good point but clipping is often over-stated as a condition, in my
> opinion.
The fact is that some amplifiers go into clipping in the course of
their day-to-day operation. It's not desireable, & it's (probably) not
intentional on the part of the designers...but to disqualify an amp
from the Positive Sound Difference Challenge because it went into
clipping is just a self-serving way of keeping your $10,000. Amps
clip. Some more than others. Proclaiming that any amp that clips
during its quote-unquote normal operation isn't a Competant amp is
also self-serving.
For that matter, the 3-point level matching caveat strikes me as a
self-serving criteria for these challenges as well. I've elaborated in
previous posts; suffice to say a more equitible way to level match
cables, interconnects, or amps in these Can You Really Hear It?
challenges would be either A) at a single frequency (nominally 1kHz)
or B) as the summed level over the full audio bandwidth. Anything else
is just acknowledging that there may actually be frequency response
aberrations that may actually be audible.
Ed Seedhouse
>The fact is that some amplifiers go into clipping in the course of
>their day-to-day operation.
Incompetantly designed ones, if so, and ones that will probably sound
"different" to a well designed one.
>It's not desireable, & it's (probably) not
>intentional on the part of the designers...but to disqualify an amp
>from the Positive Sound Difference Challenge because it went into
>clipping is just a self-serving way of keeping your $10,000.
This is nonsens. No one is claiming or has claimed that an amp that
regularly clips doesn't sound different. In fact they would predict
that they often *will* sound different.
Now why should win $10,000 for detecting differences between
amplifiers that the engineering crowd *predict* will sound different?
Ed
Howard Ferstler
And that is all well and good. The problem is that if you
knew which amp was playing at any given time (I came into
this discussion too late to know if the comparison was both
blind and properly level matched), your ability to
objectively decide on sound quality was compromised.
I see that Nousaine has offered you a challenge about
comparing amps, DBT style and carefully level matched with
each channel. I think you might benefit greatly if you took
him up on it. If you do, he will use a DBT device that will
make it impossible for you to pre-assign a winning score to
either amp. I see that a bet was involved, but I think the
challenge would best be done without a bet, and should
simply involved a desire to see what you can or cannot hear.
> I did not ascribe any explination for it just that I heard it.
I just did a series of non-blind (but still carefully level
matched) comparisons between a good AV receiver's stereo amp
section and a $3000+ amp I am reviewing for a magazine
report. As best I can tell, they sounded identical with
musical source material. Needless to say, I intend to do
some additional comparing before doing a completed review
report.
Interestingly, depending on when I was switching there were
times when one unit seemed to sound better than the other.
The musical segment and when I switched was the determining
factor in each case, however, since I could make whatever
amp I wanted to sound best sound that way by switching at
just the right time during the musical presentation. (Some
hi-fi salesmen have this trick down pat.) I also used pink
noise to level match each of the four channels (two with
each amp) and when I got through each sounded absolutely
identical. This certainly shows that whatever differences
there might have been with music, their audible frequency
responses were the same.
> If Randi wants
> to pay me to a million dollars to prove it or if some one else wants to pay me
> 10,000 dollars to prove it I will happily repeat my comparisons.
There is always a chance that a person would guess
correctly. This makes super-duper money bets a chancy thing,
unless a large number of trials were done. Also, the amps
(both of them) would have to be bench checked prior to the
comparison, just to make sure that both were working
properly. Heck, it might just be that the more upscale amp
had problems related to frequency response or even had been
designed to sound a bit different from neutral.
I think that Randi's world view does not involve proving
that decent amps are or are not identical sounding. What he
is interested in are situations where individuals
non-critically mystify real-world phenomenon and assign a
cause that involves some kind of underlying noumena that
cannot be measured or quantified.
Kant did this with God (and spent a lot of time writing
about it), and many audio buffs try to do the same thing
with subjective impressions of audio-system behavior.
Howard Ferstler
Steven Sullivan
> s888...@aol.com (S888Wheel) wrote:
> >>
> >>
> >>
> >I figured the offer was not straight up. It would cost at least 100 dollars
> >to
> >get another Yamaha reciever like the one I had. That doesn't include the time
> >involved in tracking one down.
> Not straight-up? Nowhere in your original offer was it mentioned that you no
> longer have the product you said had a different sound.
I have a Yamaha HTR-5540 -- a pretty bog-standard Yammie AVR
from several years back -- that I don't use any more.
I'll happily lend it out for the experiment.
Heck, I'll pay for shipping it to and from the test site too.
Howard Ferstler
> >Please note that this is a *cable* challenge, although your point is of
> >course quite correct, hence the pre-qualifier that amps are not driven
> >into clipping. That's one reason I hang onto my Krell - I *know* that
> >it doesn't care if it's driving a rusty nail!
> No fair pirating my Rusty-Nail challenge. But quite frankly level matching
> fully satisfies the 'clipping' issue in all but the most extreme case. In the
> SMWTMS experiments experimenters had to compare a 10-watt tube amplifier vs a
> 400-watt solid state to get a "positive sound difference result." Even in that
> case the output impedance may have influenced the results disqualifying them at
> 3-point level matching.
>
> It's a good point but clipping is often over-stated as a condition, in my
> opinion.
I agree. I just did some comparing with two amps that were
each only modestly powerful. I drove one to the point where
its peak-level lights were just flickering. (The other, much
lower-priced amp had no such indicators, but was rated at
about the same power input to the speaker load.) Both amps
still sounded the same, but this was at levels where the
sound output was really uncomfortable - especially to one of
my cats, who literally ran out of the room. At more modest
levels, where I could listen to the music without feeling
uncomfortable, the amps continued to sound the same.
Howard Ferstler
S888Wheel
>Date: 9/29/2004 4:51 PM Pacific Standard Time
>Message-id: <cjfhq...@news1.newsguy.com>
What challenge? I offered a casual invitation should you be in town and have
access to the "product" or one like it.
For a million dollars or even ten thousand dollars I would happily track it
down or find another one just like it.
>
> I'll happily accept level matching at one
>>frequency but if you need to use an equalizer to match at several
>frequencies
>>you will no longer be testing my assertion that I heard a difference (no
>>equalizers were used in my comparisons).
>
>OK how about full band pink noise? But even so IF I could duplicate the
>"sound"
>of your device with a garden variety equalizer what does that say about your
>prefered amplifier?
It would say that the only difference was frequency response. I don't *know*
that that isn't the case. I never tried to get the reciever to sound like the
Audio Research gear with an equalizer. But you expressed your skeptism about me
hearing a difference without the use of EQ.
>
> Travel expenses? So a condition of
>>this 100 dollar challenge is that you take a 500 dollar trip? C'mon.
>
>Not a problem. All you have to do is prove your case and there is no cost to
>you. And you get your hundred bucks.
Still not worth the time and effort. Anyone want to run this one by Randi?
>
>
>As for
>>the
>>number of correct scores needed for a positive, I think the standard 95%
>>certainty should apply.
>
>Those are the scores I posted. 95% which are 9 of 10; 12 of 16; 15 of 20.
>2-tailed.
>
>Frankly I'd rather take the 10,000 dollar challenge
>>or...if some one can coax Randi into extending the million dollar
>>challenge...
>
>So get to it. You've already admitted that you no longer have access to the
>device you claimed sounded 'different.'
So far the only one offering a challenge to me is you. I am far to busy a
person to "get to it" for a hundred bucks.
>
>"Frankly" I'd say you aren't interested in showing that you can 'hear'
>amplifiers.
Frankly you are right. I'm not interested in proving things like this to you.
OTOH for 10K or better yet a million bucks my interest levels go way up.
Frankly, I don't think those challenges will be offered to me. just yours.
>
>
>>But let's face it, niether will challenge my assertion without fiddling with
>>the sound of the reciever. So, if some one really doubts I heard a
>difference
>>the challenge should simply be level matched (at one frequency) and double
>>blind with scientific standards for a positive.
>
>OK; but how are you going to prove your claims with a device you no longer
>have?
I would have to track it down or get another one. Not that big a deal but 100
bucks isn't going to cut it.
This is the nexus of the high-end argument; just come over here AND
>I'll
>show you that I can "hear" the differences between these 2 amplifiers.
Yeah whatever.
>
>Then we find that you no longer have one of them.
I had no reason to keep it.
Then we are limited to
>level
>match frequencies. Then NO equalizers are allowed (even IF they are ONLY
>inserted in the comparative unit signal chain) and one is left to wonder why
>the elongation of the signal path with an equalizer wouldn't necessarily
>REDUCE
>the transparency of the original signal chain and be immediately recognizable
>by an experienced high-end listener.
Hey, you are the one who challenged *my* assertion. If you are having second
thoughts fine but my assertion involved an EQ free comparison. If I imagined a
difference then you wouldn't need any EQ to show that would you?
>
>OTOH if you are ever in town
>>and have an old Yamaha reciever from their rack systems sold in the mid
>>eighties drop me an Email.
>
>
>So this is your response?
Yes.
So you can't prove your original case because you
>no
>longer have the device you were basing the challenge on?
I could. But not for a hundred bucks. It's not like it was a one of a kind
unit.
That I have to
>supply
>both the device and spend $300 on a plane ticket plus bringing all my own
>equipment; and then if you 'fail' I'm left with all the expense of the
>experiment.
Noooooo. I said if you happen to be in town and happen to have this unit or
something like it you are welcome to come on over. You don't *have* to do
anything. I don't expect you to spend any money. I'm sorry you didn't see the
difference between your challenge and my invitation.
>
>I've taken that challenge before.
There was no challenge so it wouldn't be possible.
Do you wnat to know what happens? I've
>traveled to Maine at my own expense on a challenge from a wire company that
>if
>I 'came' to their facility they'd "show me" differences.
>
>When I got there (arrival announced weeks in advance) they refused to conduct
>the experiment claiming they never said they'd do so (even thought the
>challenge had been confirmed in letter-form.)
Either keep it casual. Like I tried to do with my invite or make the stakes
worth my while.
>
>On another occasion I paid my own expenses to proctor a blind experiment on
>power amplifiers between an audiophile and a store owner in Florida. The
>owner
>was unable to prove he was able to differentiate his $12k monoblocks from a
>used Yamaha integrated amplifier under different conditions (switched, cable
>swaps) using his personal reference systems in his reference room.
>
>So what next? This was your challenge.
There was no challenge.
You've accused me of being disengenous
No. I think your hundred dollar offer is genuine. I think your desire to use EQ
would have made your challenge disengenuous since none was used originally, but
you have waved that so I find your offer quite genuine, just not very
interesting.
>
>my old Yamaha reciever with Martin Logan CLs speakers and pay a
>>>million
>>>>>>>>>>dollars
>>>>>>>>>>or even ten thousand if I hear a difference under blind conditions
>>>I'll
>>>>>>>>>>happily
>>>>>>>>>>invite them over and find that old reciever.
>
>so exactly what is genuine about your challenge?
There is no challenge. OTOH if Randi or the other fellow who is offering 10K
would like to extend their challenges to my specific assertion I will find that
old reciever or one just like it and take them up.
You now say that you don't
>even still have it. How can you make a challenge so transparent that it's
>remotely likely that you'll ever find a challenger?
*I* haven't issued any challenges. You challenged my assertion that I heard a
difference. How did that obligate me to keep that old reciever all those many
years ago? I am not psychic.
>
>
>
>
>
>
Nousaine
Well IF there are frequency response variations that exceed the threshold of
audibility they will be completely apparent from a wideband frequency response
measurement. But the level-match challenge is just a simply way to sort out the
obviously incompetent beforehand without having to fully test the device.
Besides what's self-serving about finding out if a given amplifier or cable is
incapable of delivering the same signal to a loudspeaker terminals that was
introduced at the input (other than gain?)
Lasse
>
> I've elaborated in
> previous posts; suffice to say a more equitible way to level match
> cables, interconnects, or amps in these Can You Really Hear It?
> challenges would be either A) at a single frequency (nominally 1kHz)
> or B) as the summed level over the full audio bandwidth. Anything else
> is just acknowledging that there may actually be frequency response
> aberrations that may actually be audible.
But has anybody ever claimed that these frequency response aberrations
could not be heard? No? Then what's your point? The 'competent amps
sound the same below clipping' claim is quite easy to understand; no
clipping, pretty much linear frequency responses.
The vast majority of solid state amps have almost linear frequency response
and still these amps are not described 'as same' below clipping. So, it
cannot be very difficult to prove these differences without driving amp
to clipping or pairing vastly different designs that are no way substitutes
in the real life. This is the beef of the whole amp challenge.
Lasse Ukkonen
normanstrong
news:cjfjp...@news1.newsguy.com...
>
> The fact is that some amplifiers go into clipping in the course of
> their day-to-day operation. It's not desireable, & it's (probably)
not
> intentional on the part of the designers...but to disqualify an amp
> from the Positive Sound Difference Challenge because it went into
> clipping is just a self-serving way of keeping your $10,000. Amps
> clip. Some more than others. Proclaiming that any amp that clips
> during its quote-unquote normal operation isn't a Competant amp is
> also self-serving.
Surely you don't believe that clipping is part of normal day-to-day
operation of a high-end system.
You don't, do you?
Norm Strong
S888Wheel
>Date: 9/29/2004 8:34 PM Pacific Standard Time
>Message-id: <cjfus...@news1.newsguy.com>
Not everyone agrees. Tom seems to think I did not hear a real difference. Some
people think that if I prove I heard a real difference I might collect 10,000
dollars or better yet amillion dollars. I have not heard from the parties that
are offering 10K or a million so far. I do have a 100 dollar offer from Tom
though.
The problem is that if you
>knew which amp was playing at any given time (I came into
>this discussion too late to know if the comparison was both
>blind and properly level matched), your ability to
>objectively decide on sound quality was compromised.
The comparisons were all blind.
>
>I see that Nousaine has offered you a challenge about
>comparing amps, DBT style and carefully level matched with
>each channel. I think you might benefit greatly if you took
>him up on it. If you do, he will use a DBT device that will
>make it impossible for you to pre-assign a winning score to
>either amp. I see that a bet was involved, but I think the
>challenge would best be done without a bet, and should
>simply involved a desire to see what you can or cannot hear.
If I had ther old reciever I would happily take him up on his offer. As it
stands, it isn't worth 100 dollars to track it down or get another one like it.
My *invitation* to Tom, should he ever happen to be in town stands.
This is a chance Randi faces with his challenge regarless of that which is
being challenged. My skepticism about Randi extending his challenge to
amplification is based on my belief that he doesn't see my claim or similar
claims as so outrageous.
>unless a large number of trials were done. Also, the amps
>(both of them) would have to be bench checked prior to the
>comparison, just to make sure that both were working
>properly. Heck, it might just be that the more upscale amp
>had problems related to frequency response or even had been
>designed to sound a bit different from neutral.
My amp has been "bench tested" it is working quite well now and was working
quite well when I originally did those comparisons.
>
>I think that Randi's world view does not involve proving
>that decent amps are or are not identical sounding.
I agree that Randi is not likely interested in amp sound or the contraversy
around it. He seems to have carefully picked fringe tweaks as his target. That
is fine with me. Heck, I had some one come over years ago with a bunch of Peter
Belt tweaks. I tried them in sighted tests and couldn't hear a difference. It
does not surprise me that Randi would challenge Belt tweaks at all. I think the
million dollars is quite safe.
Howard Ferstler
>
> nous...@aol.com (Nousaine) wrote in message news:<cjd7g...@news3.newsguy.com>...
> > In
> > the
> > SMWTMS experiments experimenters had to compare a 10-watt tube amplifier
> > vs a
> > 400-watt solid state to get a "positive sound difference result." Even in
> > that
> > case the output impedance may have influenced the results disqualifying t
> > hem at
> > 3-point level matching.
> >
> > It's a good point but clipping is often over-stated as a condition, in my
> > opinion.
> The fact is that some amplifiers go into clipping in the course of
> their day-to-day operation. It's not desireable, & it's (probably) not
> intentional on the part of the designers...but to disqualify an amp
> from the Positive Sound Difference Challenge because it went into
> clipping is just a self-serving way of keeping your $10,000. Amps
> clip. Some more than others.
I have checked out some amps that clipped at maybe 100 wpc,
and let me tell you that with most speakers that was really
quite loud, and certainly louder than what I hear at live
performances. Any amp with that kind of capability with a
normal pair of speakers located in a normal-sized room will
probably never clip unless the operator is showing off.
I would say that typical maps do not clip to an audible
degree when playing normal program sources at normal levels,
even fairly loud normal levels.
> For that matter, the 3-point level matching caveat strikes me as a
> self-serving criteria for these challenges as well. I've elaborated in
> previous posts; suffice to say a more equitible way to level match
> cables, interconnects, or amps in these Can You Really Hear It?
> challenges would be either A) at a single frequency (nominally 1kHz)
> or B) as the summed level over the full audio bandwidth.
The best way to level match components by ear is to use pink
noise, and do each channel individually. (Global level
matching with both channels playing will not guarantee the
elimination of soundstaging differences if the two amps are
not absolutely equal in output with each channel.) I have
done this with amps to the extent that when the switchover
was done no audible differences could be heard. This tells
me that the amps were (1) more than decently well level
matched for future musical comparing, and also told me that
(2) their frequency responses were probably very close, at
least over the frequencies I can hear.
Howard Ferstler
Buster Mudd
Because it shows that the folks making & funding these Challenges
aren't really interested in challenging whether or not someone can
hear the difference between two different power amps, or two different
sets of cables.
Steven Sullivan
And let's keep in mind: behind nearly every amplifier or cable review in
TAS or other high end journal (not to mention many non-high-end
jnournals) is the assumption that darn near every amp sounds different if
you have the right ears and equipment and source material to reveal it.
So, either a *great* many amps have audible frequency response variations
from each other during normal use... or a great many amp reviews are
founded on dubious premises.
Buster Mudd
>
> Surely you don't believe that clipping is part of normal day-to-day
> operation of a high-end system.
> You don't, do you?
>
Not in *my* definition of "high end", no. (But how do you think the
Wavac folks would answer that?)
But the contention of the You Can't Really Hear The Difference
challenges is that all power amps sound the same, not just that all
high end power amps sound the same. In fact, most seem to go along the
lines of specifically claiming that a run-of-the-mill mid-priced power
amp is sonically indistinguishable from a high end power amp.
It's all nice to insert the caveat "when not run into clipping", but
it's completely pointless to demand that condition if the normal
operating state of an amp in real-world music-making situations
involves clipping. Nobody listens to power amps when they're not
actually *in use*!
out...@city-net.com
before controled listening tests:
"Because it shows that the folks making & funding these Challenges
aren't really interested in challenging whether or not someone can
hear the difference between two different power amps, or two different
sets of cables."
To weed out ringers whose freq response has been so changed to rise above
audibility thresholds and/or to weed out designs which do so to create an
audible difference while falling short of a desired flat freq response in
the 20 - 20 k range. Either case is a waste of time, anyone playing
around with an eq for 5 seconds knows freq response differences can be
heard. Most amp/wire claims to difference appeal to some inherent quality
other then freq response. When some audio mag says that audible
differences jump out at you when hearing a $800 amp when compared to a
$8000 amp they are not making appeals to freq differences and often there
are measurements to confirm same. All testing conditions are to confirm
that we are comparing apples to apples where audible thresholds are
already known,ie. level matching and freq response and current limiting
with a given load.
Steven Sullivan
And, too, there's the issue of cables -- surely they don't 'clip'
in normal use. Do you think it plausible that all those
cables reviewed in high-end journals *really* differnet sounding
from each other, Buster?
Steven Sullivan
> "normanstrong" <norman...@comcast.net> wrote in message news:<cji6v...@news3.newsguy.com>...
> >
> > Surely you don't believe that clipping is part of normal day-to-day
> > operation of a high-end system.
> > You don't, do you?
> >
> Not in *my* definition of "high end", no. (But how do you think the
> Wavac folks would answer that?)
> But the contention of the You Can't Really Hear The Difference
> challenges is that all power amps sound the same, not just that all
> high end power amps sound the same. In fact, most seem to go along the
> lines of specifically claiming that a run-of-the-mill mid-priced power
> amp is sonically indistinguishable from a high end power amp.
And , using the same loose rhetoric,
the contention of the High End Establishment is that all power
amps sound different.
It has already been shown in publlished trials (that are
challenged by audiophiles, of course) that a mass market
power amp may indeed be sonically indistinguishable from
a high end one. Tom Nousaine can fill you in on the
details.
Do you think it would turn out that most amps sound
different, or the same, if the trials were repeated
with various other combinations?
> It's all nice to insert the caveat "when not run into clipping", but
> it's completely pointless to demand that condition if the normal
> operating state of an amp in real-world music-making situations
> involves clipping.
But people are saying it doesn't; you're saying it does.
Who's correct? Is my H-K AVR clipping during normal use?
> Nobody listens to power amps when they're not
> actually *in use*!
I would hope that some high-end listeners can detect clipping.
Wouldn't that bother them?
B&D
"out...@city-net.com" <out...@city-net.com> wrote:
Wouldn't be more useful to explain *why* some differences occur in "sound"
of amplifiers.
After all, we know, and it is not controversial to the best of my knowledge:
1. Non flat response
2. Ability to drive certain loads (like electrostatics that can end up at
highly reactive low impedances at the upper frequencies, or a cone speaker
that has an impedance dip at some frequencies that would tax an amplifer too
much)
3. Clipping levels of amps (actual power rating) and the type of distortion
in that case (odd or even harmonics)
4. Open loop response of the amp *if* there is a severe difference between
the two and the control feedback loop is sufficently slow (I will leave off
"time smearing" here because some people say it is irrelevant)
Because 1-4 occur in all amps to a greater or lesser degree, wouldn't it be
more USEFUL to people to understand what about an amp makes it appropriate
and what makes something inappropriate in a lot of cases?
Just a thought ...
Stewart Pinkerton
>Wouldn't be more useful to explain *why* some differences occur in "sound"
>of amplifiers.
>
>After all, we know, and it is not controversial to the best of my knowledge:
>
>1. Non flat response
Agreed, but the level-matching pre-condition removes this as an issue
for so-called 'high end' amplifiers
>2. Ability to drive certain loads (like electrostatics that can end up at
>highly reactive low impedances at the upper frequencies, or a cone speaker
>that has an impedance dip at some frequencies that would tax an amplifer too
>much)
Agreed, but the non-clipping pre-condition removes this as an issue
for so-called 'high end' amplifiers
>3. Clipping levels of amps (actual power rating) and the type of distortion
>in that case (odd or even harmonics)
Agreed, except that the distortion spectrum *in clipping* has not been
shown to make an audible difference, and the non-clipping
pre-condition removes this as an issue for so-called 'high end'
amplifiers
>4. Open loop response of the amp *if* there is a severe difference between
>the two and the control feedback loop is sufficently slow (I will leave off
>"time smearing" here because some people say it is irrelevant)
You'd have to show that this makes any *audible* difference
>Because 1-4 occur in all amps to a greater or lesser degree, wouldn't it be
>more USEFUL to people to understand what about an amp makes it appropriate
>and what makes something inappropriate in a lot of cases?
Not really, unless you are *completely* ignorant about the basics, in
which case you have no business calling yourself an audiophile.....
Chung
You're making it more complicated than it is. Amps sound different if
(1) Frequency response differences exist that are above threshold of
hearing.
(2) Distortion level differences that are above threshold of hearing.
(3) Noise level differences that are above threshold of hearing.
Open loop responses are irrelevant, since you do not use the amp
open-loop. Ability to drive the loads is measured directly by frequency
response and distortion measurements at the proper power levels when
driving the load.
And don't confuse measurements with specs.
Nousaine
Actually the assumption is not that 'nearly every' amplifier sounds different;
I cannot ever personally recall a single high-end journal review that EVER said
that an amplifier ever sounded like any other amplifier. EVER.
B&D
<chun...@covad.net> wrote:
> Open loop responses are irrelevant, since you do not use the amp
> open-loop.
Actually you do use it open loop. A feedback loop has a certain speed, and
under that speed the response of the amp is closer to the open loop response
than the closed loop response. If the two responses are drastically
different, the possibility is there to have unintended and difficult to
measure distortion.
chung
With all due respect, I don't think you understand feedback amplifiers.
In any event, you listen to the amplifier, *NOT* the amplifier with its
loop open. Can you tell two amps apart, if they have different open loop
responses?
B&D
<chun...@covad.net> wrote:
> B&D wrote:
>> On 10/2/04 2:19 PM, in article cjmrg...@news4.newsguy.com, "Chung"
>> <chun...@covad.net> wrote:
>>
>>
>>> Open loop responses are irrelevant, since you do not use the amp
>>> open-loop.
>>
>>
>> Actually you do use it open loop. A feedback loop has a certain speed, and
>> under that speed the response of the amp is closer to the open loop response
>> than the closed loop response. If the two responses are drastically
>> different, the possibility is there to have unintended and difficult to
>> measure distortion.
>
> With all due respect, I don't think you understand feedback amplifiers.
I have designed them and continue to do so. Feedback has a delay associated
with it - and events happening faster than the speed of the loop will behave
more open loop than closed.
> In any event, you listen to the amplifier, *NOT* the amplifier with its
> loop open. Can you tell two amps apart, if they have different open loop
> responses?
During a transient event, with a sufficiently slow feedback loop - you may
be hearing the open loop response more than closed loop - basic control
theory. In a competently designed amplifier the responses should be similar
enough to not matter as much.
chung
> On 10/3/04 1:16 PM, in article cjpc5...@news4.newsguy.com, "chung"
> <chun...@covad.net> wrote:
>
>
>>B&D wrote:
>>
>>>On 10/2/04 2:19 PM, in article cjmrg...@news4.newsguy.com, "Chung"
>>><chun...@covad.net> wrote:
>>>
>>>
>>>
>>>>Open loop responses are irrelevant, since you do not use the amp
>>>>open-loop.
>>>
>>>
>>>Actually you do use it open loop. A feedback loop has a certain speed, and
>>>under that speed the response of the amp is closer to the open loop response
>>>than the closed loop response. If the two responses are drastically
>>>different, the possibility is there to have unintended and difficult to
>>>measure distortion.
>>
>>With all due respect, I don't think you understand feedback amplifiers.
>
>
> I have designed them and continue to do so. Feedback has a delay associated
> with it - and events happening faster than the speed of the loop will behave
> more open loop than closed.
In that case, those things are all measureable closed loop, no? Do you
agree that it is irrelevant to the listener what the open-loop response
of the amp is?
>
>
>>In any event, you listen to the amplifier, *NOT* the amplifier with its
>>loop open. Can you tell two amps apart, if they have different open loop
>>responses?
>
>
> During a transient event, with a sufficiently slow feedback loop - you may
> be hearing the open loop response more than closed loop - basic control
> theory.
In that case, those are closed loop observations, no? Why confuse the
issues by bringing up the open-loop response?
> In a competently designed amplifier the responses should be similar
> enough to not matter as much.
You are not being clear. Are you saying that in a competent design, the
closed loop response should be similar to the open loop response? Wow,
that would be strange coming from one supposedly familiar with basic
control theory.
Or are you saying that in competently designed amps, the open loop
responses should be similar?
What exactly are you trying to say?
Stewart Pinkerton
And if the input stage is tailored to prevent the passing of
disturbingly high frequencies, the 'problem' will not exist at all.
Stewart Pinkerton
It's not at all difficult to measure, the HF IMD test is the
appropriate measure for any such problems. However, in the 21st
century, you will only find such problems in the most incompetent
designs - usually at very high prices!
Buster Mudd
> <addendum to my last reply to Buster Mudd>
>
> And, too, there's the issue of cables -- surely they don't 'clip'
> in normal use. Do you think it plausible that all those
> cables reviewed in high-end journals *really* differnet sounding
> from each other, Buster?
Not sure how this pertains to my previous post re: power amps.
Buster Mudd
>
> Do you think it would turn out that most amps sound
> different, or the same, if the trials were repeated
> with various other combinations?
>
Who said anything about *most*? I think it would turn out that *some*
amps sound different if the conditions of the trial were that the
equipment be used in its normal operating state, rather than the
artificially imposed conditions of these comparisons. It would not
surprise me in the least to learn that quite a few power amps ranging
from a few hundred to tens of thousands of dollars are sonically
indistinguishable. It would also surprise me immensely if I (or any
half-assed audiophile with a smidgeon of analytical listening
experience) couldn't pick out a Peavey CS800 or Carver PM-1.5 versus a
Crown MacroTech 2400 or Crest 9001 10 out of 10 times when driving a
passive 3-way loudspeaker to 105 dB SPL @ 1 meter in a >8000 cu.foot
room...i.e., a normal day-to-day application for these power amps.
>
> But people are saying it doesn't; you're saying it does.
> Who's correct? Is my H-K AVR clipping during normal use?
>
How would I know? Do you know? Can you tell? If you can't, do you
care? Or more to the point: if you can't tell, *why* do you care?
> I would hope that some high-end listeners can detect clipping.
The operative word in that sentence being *some*.
> Wouldn't that bother them?
Moreso if they identified it as clipping...but if they hear clipping
and identify it as "bloom" or "pace" or "effulgence" or "whimsy" or
"sheen" or any of the other euphemisms which come out of audiophiles'
mouths, then all bets are off. Do you honestly believe there *aren't*
any self-described audiophiles in the world who find a clipping power
amp somehow pleasantly euphonic?
Steven Sullivan
It pertains to the post you made before that one, wher eyou wrote,
objecting to the standard conditions for blind challenges:
"Because it shows that the folks making & funding these Challenges
aren't really interested in challenging whether or not someone can
hear the difference between two different power amps, or two different
sets of cables."
Steven Sullivan
> Steven Sullivan <ssu...@panix.com> wrote in message news:<cjmdl...@news1.newsguy.com>...
> >
> > Do you think it would turn out that most amps sound
> > different, or the same, if the trials were repeated
> > with various other combinations?
> >
> Who said anything about *most*?
You said that one sides contends that All Amps Sound the Same,
which is not the case. I'm trying to get a more careful
claim out of you.
> I think it would turn out that *some*
> amps sound different if the conditions of the trial were that the
> equipment be used in its normal operating state, rather than the
> artificially imposed conditions of these comparisons.
That's pretty much what teh 'All Amps Soudn the Same' faction says too,
minus the remark about artifical conditions.
> It would not
> surprise me in the least to learn that quite a few power amps ranging
> from a few hundred to tens of thousands of dollars are sonically
> indistinguishable. It would also surprise me immensely if I (or any
> half-assed audiophile with a smidgeon of analytical listening
> experience) couldn't pick out a Peavey CS800 or Carver PM-1.5 versus a
> Crown MacroTech 2400 or Crest 9001 10 out of 10 times when driving a
> passive 3-way loudspeaker to 105 dB SPL @ 1 meter in a >8000 cu.foot
> room...i.e., a normal day-to-day application for these power amps.
These are amps and conditions normally found in home audio?
> > But people are saying it doesn't; you're saying it does.
> > Who's correct? Is my H-K AVR clipping during normal use?
> >
> How would I know? Do you know? Can you tell? If you can't, do you
> care? Or more to the point: if you can't tell, *why* do you care?
I'm exploring your claims. Persobnally, I'm of the 'amps are
more likely to sound the same than not' camp', so I tend not to care.
I buy *receivers* that have the features and power I want.
> > I would hope that some high-end listeners can detect clipping.
> The operative word in that sentence being *some*.
> > Wouldn't that bother them?
> Moreso if they identified it as clipping...but if they hear clipping
> and identify it as "bloom" or "pace" or "effulgence" or "whimsy" or
> "sheen" or any of the other euphemisms which come out of audiophiles'
> mouths, then all bets are off. Do you honestly believe there *aren't*
> any self-described audiophiles in the world who find a clipping power
> amp somehow pleasantly euphonic?
So, what they don't know, can't hurt them. But shouldn't a spade be
called a spade, particularly in journals devoted to reviewing spades?
B&D
<chun...@covad.net> wrote:
> B&D wrote:
>> I have designed them and continue to do so. Feedback has a delay associated
>> with it - and events happening faster than the speed of the loop will behave
>> more open loop than closed.
>
> In that case, those things are all measureable closed loop, no? Do you
> agree that it is irrelevant to the listener what the open-loop response
> of the amp is?
It all depends if the open loop response is capable of influencing the sound
of transient events - and it isn't always irrelevant...
>> During a transient event, with a sufficiently slow feedback loop - you may
>> be hearing the open loop response more than closed loop - basic control
>> theory.
>
> In that case, those are closed loop observations, no? Why confuse the
> issues by bringing up the open-loop response?
It should be if you were to run a series of transient events through the amp
and look at the phase and amplitude response. I have no idea how one would
do a sufficiently complex set of tests in closed loop format to see -
perhaps a series of triangle waves or square waves? I don't know.
>> In a competently designed amplifier the responses should be similar
>> enough to not matter as much.
>
> You are not being clear. Are you saying that in a competent design, the
> closed loop response should be similar to the open loop response? Wow,
> that would be strange coming from one supposedly familiar with basic
> control theory.
What I am saying is that if the loop were fast enough, AND the open loop
response were a stone's throw from the closed loop response it would be
hardly noticeable. It is NOT a given, though.
Chung
> On 10/4/04 7:42 PM, in article cjsn4...@news1.newsguy.com, "chung"
> <chun...@covad.net> wrote:
>
>> B&D wrote:
>
>>> I have designed them and continue to do so. Feedback has a delay associated
>>> with it - and events happening faster than the speed of the loop will behave
>>> more open loop than closed.
>>
>> In that case, those things are all measureable closed loop, no? Do you
>> agree that it is irrelevant to the listener what the open-loop response
>> of the amp is?
>
> It all depends if the open loop response is capable of influencing the sound
> of transient events - and it isn't always irrelevant...
>
>>> During a transient event, with a sufficiently slow feedback loop - you may
>>> be hearing the open loop response more than closed loop - basic control
>>> theory.
>>
>> In that case, those are closed loop observations, no? Why confuse the
>> issues by bringing up the open-loop response?
>
> It should be if you were to run a series of transient events through the amp
> and look at the phase and amplitude response. I have no idea how one would
> do a sufficiently complex set of tests in closed loop format to see -
> perhaps a series of triangle waves or square waves? I don't know.
The problem you have is that you keep trying to refer to the open-loop
response, when the listener (or tester) is hearing the closed-loop
response. The open-loop response is irrelevant to the listener. Why
would the listener be interested to finding out what the open-loop
response is (other than academic curiosity)?
>
>>> In a competently designed amplifier the responses should be similar
>>> enough to not matter as much.
>>
>> You are not being clear. Are you saying that in a competent design, the
>> closed loop response should be similar to the open loop response? Wow,
>> that would be strange coming from one supposedly familiar with basic
>> control theory.
>
> What I am saying is that if the loop were fast enough, AND the open loop
> response were a stone's throw from the closed loop response it would be
> hardly noticeable. It is NOT a given, though.
You are still not being clear. How much is a "stone's throw"? What is
not being noticeable? Is it a requirement for competent amps that the
closed loop response be a "stone's throw" from the open loop response?
Buster Mudd
> Buster Mudd <mr_fu...@mail.com> wrote:
> > Steven Sullivan <ssu...@panix.com> wrote in message news:<cjmdl...@news1.newsguy.com>...
>
> > >
> > > Do you think it would turn out that most amps sound
> > > different, or the same, if the trials were repeated
> > > with various other combinations?
> > >
>
> > Who said anything about *most*?
>
> You said that one sides contends that All Amps Sound the Same,
> which is not the case. I'm trying to get a more careful
> claim out of you.
>
If it's not the case, then I've been getting a misrepresentation of
the contentions from posts I've read here on RAHE. (Until I started
reading this ng, I'd never heard *anyone* claim all power amps sound
the same, much less offer money to anyone who could pick them out
blind.) Have I misunderstood the basic premise of (for lack of a
better word) The Objectivists, that all competantly-designed power
amplifiers are sonically indistinguishable? Are they really saying
that MOST competantly-designed power amplifiers are sonically
indistinguishable? Or that SOME competantly-designed power amplifiers
are sonically indistinguishable?
> > It would not
> > surprise me in the least to learn that quite a few power amps ranging
> > from a few hundred to tens of thousands of dollars are sonically
> > indistinguishable. It would also surprise me immensely if I (or any
> > half-assed audiophile with a smidgeon of analytical listening
> > experience) couldn't pick out a Peavey CS800 or Carver PM-1.5 versus a
> > Crown MacroTech 2400 or Crest 9001 10 out of 10 times when driving a
> > passive 3-way loudspeaker to 105 dB SPL @ 1 meter in a >8000 cu.foot
> > room...i.e., a normal day-to-day application for these power amps.
>
> These are amps and conditions normally found in home audio?
>
So the Indistinguishable Power Amp Challenge only applies to home
audio? Fair enough, I suppose...certainly limits the number of amps
which fit the criteria of the contention though. So you're saying I'm
definitely mistaken; no one is claiming that all competantly-designed
power amplifiers are sonically indistinguishable, right? What they're
saying (if I understand the conditions & caveats that keep cropping
up) is that A FEW competantly-designed power amplifiers, a subset of
all available power amps which definitely does not including
professional power amps (& definitely does not include amps that
actually sound different from one another!) are sonically
indistinguishable. That's the claim?
>
> > > I would hope that some high-end listeners can detect clipping.
>
> > The operative word in that sentence being *some*.
>
> > > Wouldn't that bother them?
>
> > Moreso if they identified it as clipping...but if they hear clipping
> > and identify it as "bloom" or "pace" or "effulgence" or "whimsy" or
> > "sheen" or any of the other euphemisms which come out of audiophiles'
> > mouths, then all bets are off. Do you honestly believe there *aren't*
> > any self-described audiophiles in the world who find a clipping power
> > amp somehow pleasantly euphonic?
>
> So, what they don't know, can't hurt them. But shouldn't a spade be
> called a spade, particularly in journals devoted to reviewing spades?
I'm with you 100% on that item!
B&D
<chun...@covad.net> wrote:
>> It should be if you were to run a series of transient events through the amp
>> and look at the phase and amplitude response. I have no idea how one would
>> do a sufficiently complex set of tests in closed loop format to see -
>> perhaps a series of triangle waves or square waves? I don't know.
>
> The problem you have is that you keep trying to refer to the open-loop
> response, when the listener (or tester) is hearing the closed-loop
> response. The open-loop response is irrelevant to the listener. Why
> would the listener be interested to finding out what the open-loop
> response is (other than academic curiosity)?
The listener will hear both the open loop and closed loop response. In the
steady state condition you will hear the closed loop response. In
transients the sound will be influenced by the open loop response.
Nousaine
This is a clever ruse to divert the issue. What I claim is that no person or
persons have ever shown an ability to differentiate level matched amplifiers
under bias controlled test conditions which have generally included level
matching at 100,1000 and 10,000 Hz at the MOST stringent (but even then not
often invoked) and blind presentations.
As early as 1990 there had been over 2 dozen controlled listening comparisons
published in the popular press and as of that date the only 'positive' results
included ampliifers with high-output impedance, an obviously malfunctioning
unit and a comparison of 10 watts vs 400. Two of those tests had been conducted
by the ABX people. In 1991 Stereo Review published an article about tubes vs
transistors that showed that a tubed unit with a high output impedance had
frequemcy response errors of 2-3 dB in the mid-band.
Subsequent to that I've conducted a blind test of a PASS Aleph ($12 K pair of
monoblocks) vs a Yamaha Integrated amplifier in the personal reference system
of a high-end audio store owner using his own program material who was unable
to reliably differentiate his reference (PASS) from the Yamaha driving his
reference speakers in his reference room (also show room) using ABX switched
comparisons and cable swaps in 2 separate experiments.
What is seriously lacking in this discussion isn't a definitve experiment
showing that all competent amplifiers sound the same BUT a definitive level
matched blind comparison experiment that shows that ANY of them actually DO.
out...@city-net.com
comparisons
published in the popular press and as of that date the only 'positive'
results
included ampliifers with high-output impedance, an obviously
malfunctioning
unit and a comparison of 10 watts vs 400. Two of those tests had been
conducted
by the ABX people. In 1991 Stereo Review published an article about tubes
vs
transistors that showed that a tubed unit with a high output impedance had
frequemcy response errors of 2-3 dB in the mid-band.
"
Not to mention the "test" done by bob carver and the stereophile staff to
identify a tube amp of their choice and his ss amp tweeked to sound like
it.
out...@city-net.com
the
steady state condition you will hear the closed loop response. In
transients the sound will be influenced by the open loop response."
This is a testable notion, if you think it a candidate for spotting
differences among amps, do the testing. At some point armchair
speculation must give way to testing.
Steven Sullivan
> Steven Sullivan <ssu...@panix.com> wrote in message news:<cjvc9...@news2.newsguy.com>...
> > Buster Mudd <mr_fu...@mail.com> wrote:
> > > Steven Sullivan <ssu...@panix.com> wrote in message news:<cjmdl...@news1.newsguy.com>...
> >
> > > >
> > > > Do you think it would turn out that most amps sound
> > > > different, or the same, if the trials were repeated
> > > > with various other combinations?
> > > >
> >
> > > Who said anything about *most*?
> >
> > You said that one sides contends that All Amps Sound the Same,
> > which is not the case. I'm trying to get a more careful
> > claim out of you.
> >
> If it's not the case, then I've been getting a misrepresentation of
> the contentions from posts I've read here on RAHE. (Until I started
> reading this ng, I'd never heard *anyone* claim all power amps sound
> the same, much less offer money to anyone who could pick them out
> blind.)
No one here claims 'all power amps sound the same', with no
qualification whatsoever.
And even over on recording engineering forums, like
Massenberg's, I've seen peopel come out in favor
of blind testing to *verify* a claim of amp difference.
I highly doubt guys like like Nika Aldrich and Dan Lavry have much
patience for the 'of course it soudns differnet, everyone
knows that' stance.
My impression is taht recordeing engineers rarely bother to do blind testing,
but they also don't seem to go ion for wild claims of
audio difference , either. Exceptions exist of course.
> Have I misunderstood the basic premise of (for lack of a
> better word) The Objectivists, that all competantly-designed power
> amplifiers are sonically indistinguishable?
Yes, when not driven into distortion.
> Are they really saying
> that MOST competantly-designed power amplifiers are sonically
> indistinguishable? Or that SOME competantly-designed power amplifiers
> are sonically indistinguishable?
Why don't you do some googling of 'objectivist' viewpoints,
and get back to me? You can start by googling past
threads on this ng.
> > > It would not
> > > surprise me in the least to learn that quite a few power amps ranging
> > > from a few hundred to tens of thousands of dollars are sonically
> > > indistinguishable. It would also surprise me immensely if I (or any
> > > half-assed audiophile with a smidgeon of analytical listening
> > > experience) couldn't pick out a Peavey CS800 or Carver PM-1.5 versus a
> > > Crown MacroTech 2400 or Crest 9001 10 out of 10 times when driving a
> > > passive 3-way loudspeaker to 105 dB SPL @ 1 meter in a >8000 cu.foot
> > > room...i.e., a normal day-to-day application for these power amps.
> >
> > These are amps and conditions normally found in home audio?
> >
> So the Indistinguishable Power Amp Challenge only applies to home
> audio?
Are home amps expected to be driven into clipping on a daily basis?
Is that what the adverts mean when they describe the sound of
the product?
Fair enough, I suppose...certainly limits the number of amps
> which fit the criteria of the contention though. So you're saying I'm
> definitely mistaken; no one is claiming that all competantly-designed
> power amplifiers are sonically indistinguishable, right?
That's not waht you originally wrote -- you wrote simply
taht there's a faction taht believes *all amps sound the same*. Period.
There is no such faction, taht I've ever encountered.
Again, do your research,a nd get back to me. It's not like there's not
TONS of repetition of these points out there. You can start with the
posts of Mssrs. Nousaine and Pinkerton, which I thought you'd been
reading.
Stewart Pinkerton
That is not necessarily true, and is certainly *not* true of a
well-designed amplifier which absorbs transients at its input.
Stewart Pinkerton
>Steven Sullivan <ssu...@panix.com> wrote in message news:<cjvc9...@news2.newsguy.com>...
>> Buster Mudd <mr_fu...@mail.com> wrote:
>> > Steven Sullivan <ssu...@panix.com> wrote in message news:<cjmdl...@news1.newsguy.com>...
>>
>> > >
>> > > Do you think it would turn out that most amps sound
>> > > different, or the same, if the trials were repeated
>> > > with various other combinations?
>> > >
>>
>> > Who said anything about *most*?
>>
>> You said that one sides contends that All Amps Sound the Same,
>> which is not the case. I'm trying to get a more careful
>> claim out of you.
>>
>If it's not the case, then I've been getting a misrepresentation of
>the contentions from posts I've read here on RAHE. (Until I started
>reading this ng, I'd never heard *anyone* claim all power amps sound
>the same, much less offer money to anyone who could pick them out
>blind.) Have I misunderstood the basic premise of (for lack of a
>better word) The Objectivists, that all competantly-designed power
>amplifiers are sonically indistinguishable? Are they really saying
>that MOST competantly-designed power amplifiers are sonically
>indistinguishable? Or that SOME competantly-designed power amplifiers
>are sonically indistinguishable?
Someone's certainly doing some misrepresenting, but that would be you!
How did you move from "all competantly (sic)-designed power amplifiers
are sonically indistinguishable" to "All Amps Sound the Same"?
We're well aware of the existence of many amps which sound different
due to *not* being competently designed - mostly with high-end labels
attached!
>> > It would not
>> > surprise me in the least to learn that quite a few power amps ranging
>> > from a few hundred to tens of thousands of dollars are sonically
>> > indistinguishable. It would also surprise me immensely if I (or any
>> > half-assed audiophile with a smidgeon of analytical listening
>> > experience) couldn't pick out a Peavey CS800 or Carver PM-1.5 versus a
>> > Crown MacroTech 2400 or Crest 9001 10 out of 10 times when driving a
>> > passive 3-way loudspeaker to 105 dB SPL @ 1 meter in a >8000 cu.foot
>> > room...i.e., a normal day-to-day application for these power amps.
>>
>> These are amps and conditions normally found in home audio?
>>
>So the Indistinguishable Power Amp Challenge only applies to home
>audio?
No, but the 'below clipping' rule still applies.
>Fair enough, I suppose...certainly limits the number of amps
>which fit the criteria of the contention though. So you're saying I'm
>definitely mistaken; no one is claiming that all competantly-designed
>power amplifiers are sonically indistinguishable, right?
Firstly, it's COMPETENT. Secondly, people are indeed saying that all
competently-designed amps sound the same below clipping.
> What they're
>saying (if I understand the conditions & caveats that keep cropping
>up) is that A FEW competantly-designed power amplifiers, a subset of
>all available power amps which definitely does not including
>professional power amps (& definitely does not include amps that
>actually sound different from one another!) are sonically
>indistinguishable. That's the claim?
No - see above. The 'conditions and caveats' simply excude amps with
non-flat frequency response, and constrain the outputs to below the
clipping level of the least powerful amp in the comparison. You have a
problem with those simple and obvious pre-conditions? You think this
affects 'slam', 'inner detail', 'rhythm and pace', 'ambience',
'microdynamics', and all the other high end bullshit terms?
jjn...@sonic.net
Sure, if you're referring to obsolete dreck designs like a 741 op amp and
the like.
If one can hear this going on then that amplifier cannot be said to be
'nominally competent'. What news!
Why worry about it these days?
Lasse
>
> If it's not the case, then I've been getting a misrepresentation of
> the contentions from posts I've read here on RAHE. (Until I started
> reading this ng, I'd never heard *anyone* claim all power amps sound
> the same, much less offer money to anyone who could pick them out
> blind.) Have I misunderstood the basic premise of (for lack of a
> better word) The Objectivists, that all competantly-designed power
> amplifiers are sonically indistinguishable? Are they really saying
> that MOST competantly-designed power amplifiers are sonically
> indistinguishable? Or that SOME competantly-designed power amplifiers
> are sonically indistinguishable?
Haven't you read the rules of the Richard Clarks Amp Challenge? In that
case you should. The conditions are defined quite well and I see very
little room for misunderstanding. Clarks challenge includes car and home
amps, and it would be quite possible that it had extended to pro gear by
now. I have provided you the complete rules below. Note that they are year
2000 version that do not include home amps, but current rules do. Current
challenge is also open for anyone.
If a competent amp is defined as an amp that qualifies for conditions
the Amp Challenge, then we can say that the objectivist claim is
'all competent amps are sonically indistinguishable when working inside
designed parameters'. If you object this definition, then would you be
so kind and point out the error in demands.
These are the conditions for the amp stated in Richard Clarks Amp
Challenge:
"Amplifier Comparison Test Conditions
1. Amplifier gain controls - of both channels - are matched to within
+- .05 dB.
2. Speaker wires on both amps are properly wired with respect to
polarity. (+ and -)
3. That neither amp has signal phase inversion. If so correction will
be made in #2 above.
4. That neither amp is loaded beyond its rated impedance.
5. That all amplifiers with signal processors have those circuits
bypassed. This includes bass boost circuits, filters, etc. If
frequency tailoring circuits cannot be completely bypassed an
equalizer will be inserted in the signal path of one (only one and the
listener can decide which) of the amps to compensate for the
difference. Compensation will also be made for input and output
loading that affects frequency response. Since we are only listening
for differences in the sonic signature of circuit topology, the
addition of an EQ in one signal path only should make the test even
easier.
6. That neither amp exhibits excessive noise (including RFI).
7. That each amp can be properly driven by the test setup. Not
normally a problem but it is theoretically a problem.
8. That the L and R channels are not reversed in one amp.
9. That neither amp has excessive physical noise or other indicators
that can be observed by the listener.
10. That neither amp has DC OFFSET that causes audible pops when its
output is switched.
11. That the channel separation of all amps in the test is at least 30
dB from 20Hz to 20kHz."
Lasse Ukkonen
THE $10,000 AMPLIFIER CHALLENGE RULES {April 21, 2000}
By Richard Clark
There is no question that all amps are not the same. It is very easy
to measure large differences in the performance of amplifiers. This is
true in nearly every known specification, including power, noise,
distortion, etc. My experience has led me to believe that even though
these differences can be easily measured, hearing those differences
may not be so easy. Given the relatively small magnitude of
performance differences, there is a giant step between amplifier
performance and our ability to hear performance differences.
It is claimed by designers, manufacturers and especially salespersons
that differences in amplifiers are clearly audible. Reasons include
"obvious" advantages of one type of circuit topology over another. For
example, it is claimed that certain designs have a smoother midrange
response whereas other amplifiers exhibit tighter bass. Tube fanatics
claim that tube amplifiers have that "warm" sound we all need in our
systems.
Such descriptive terms are certainly subject to personal
interpretation. It is not my intention to determine if one particular
amplifier is better than another amplifier. Differences in the quality
of the discrete components and constructions are more appropriate for
settling the issue of "good - better - best." The sole purpose of my
amplifier challenge is to determine if the differences in amplifiers
are audible.
What differences are Audible?
I believe the perceived differences in amplifiers are all due to
various factors that can be explained with basic physics and
elementary psyco-acoustics. For instance, if two amplifiers are not
carefully matched in volume, and one amp is slightly louder than the
other, then it would be a simple matter to detect such a difference.
In such an example it is important to understand that it is not the
circuit topology, quality of the component, design excellence, or
superb marketing and packaging that caused the noticeable difference -
it was an error in the test setup! It is my present belief that as
long as a modern amplifier is operated within its linear range (below
overload), the differences between amps are inaudible to the human
ear.
Comparing Amps
The idea here is for a test subject to scientifically demonstrate
his/her ability to hear differences in amplifiers. It is our job to
carefully match the amps so that we are comparing "apples to apples"
instead of "oranges to frogs." This means that we sure wouldn't want
to compare one amplifier that had + 12 dB of high frequency boost
against another amplifier that was adjusted for + 12 dB of bass boost.
Such a test would be easy to pass - even on identical amplifiers with
consecutive serial numbers.
For our comparison test, we aren't concerned with which amplifier
sounds best to the test subject. We only require that the listener be
able to identify each amplifier when it is powering the speakers.
Since many folks seem to believe that amplifiers
have some kind of distinctive sonic character, this test should be
easy to pass. Right? After all, we're talking about comparing those
harsh sounding, high distortion, squeaky "widget As" to those warm
sounding, smooth, bass hog "widget Bs."
Now pay particular attention to the following sections. Since we're
looking for differences in amplifiers, and we already know that those
differences are probably going to be very, very small, it is important
that the parameters under our control be carefully adjusted so as to
be equal as possible. This means that we must be cognizant of
differences we might unknowingly introduce between amp A and amp B.
They must be adjusted as identical as possible. We already mentioned
the importance of volume. The same goes for the L and R balance. It
sure would be easy to choose an amplifier that exhibited left side
bias over a balanced amp. Right?
Well, in order to keep this amplifier comparison test fair, there are
a few other parameters that must be considered. I'll list them all in
the following section.
Amplifier Comparison Test Conditions
1. Amplifier gain controls - of both channels - are matched to within
+- .05 dB.
2. Speaker wires on both amps are properly wired with respect to
polarity. (+ and -)
3. That neither amp has signal phase inversion. If so correction will
be made in #2 above.
4. That neither amp is loaded beyond its rated impedance.
5. That all amplifiers with signal processors have those circuits
bypassed. This includes bass boost circuits, filters, etc. If
frequency tailoring circuits cannot be completely bypassed an
equalizer will be inserted in the signal path of one (only one and the
listener can decide which) of the amps to compensate for the
difference. Compensation will also be made for input and output
loading that affects frequency response. Since we are only listening
for differences in the sonic signature of circuit topology, the
addition of an EQ in one signal path only should make the test even
easier.
6. That neither amp exhibits excessive noise (including RFI).
7. That each amp can be properly driven by the test setup. Not
normally a problem but it is theoretically a problem.
8. That the L and R channels are not reversed in one amp.
9. That neither amp has excessive physical noise or other indicators
that can be observed by the listener.
10. That neither amp has DC OFFSET that causes audible pops when its
output is switched.
11. That the channel separation of all amps in the test is at least 30
dB from 20Hz to 20kHz.
In addition to these requirements the test will be conducted according
to the following rules.
Amplifier Test Comparison Rules
1. To make things easy we would prefer to use high quality home type
loudspeakers for the test. If our speakers are not acceptable, the
listener can provide any commercially available speaker system as long
as it uses dynamic drivers. The actual measured impedance cannot
exceed the rated load impedance of the amplifiers tested. If, however,
the tester would like to perform the test in a car, we will use a car,
however, it will have to be provided by the test subject. For
practicality we will have to limit the number of amplifier channels to
four or less.
2. Amplifiers will be powered from the same power supply at a nominal
14 volts DC. (any voltage is OK as long as it is the same for both
amps)
3. The test can be conducted at any volume desired; however, the amps
will not be allowed to clip. In other words, listening volume can not
exceed the power capacity of the smallest amp of the pair being
tested. (power capacity will be defined as clipping or 2%THD 20Hz to
10kHz, whichever is less)
4. No test signals can be used - only commercially available music.
5. The listener can compare two amps at a time for as long as desired.
For practical reasons we would like to keep this at least no more than
a few hours. A test session will consist of 12 A/B sequences. Passing
the test will require a positive identification of each amp for all 12
sequences. Remember, guessing will get you about 6 out of 12. If the
differences are so great, and a subject can really hear the
difference, then he/she should be able to do so for all 12 sequences.
6. To win the $10,000.00, the listener must pass two complete sessions
of 12 comparisons. Passing the test means 24 correct responses.* The
amp of choice can be compared to the same or a different amp in each
session - challengers choice. We have many amplifiers in our demo
inventory such as, but not limited to, Alpine, Rockford, Kicker,
Phoenix Gold, Precision Power, MTX, Adcom, Kenwood, Pioneer, Sony,
etc. You can pick any of them or bring your own.
7. All amps must be brand name, standard production, linear voltage
amplifiers. This does not exclude high current amps. Amps can not be
modified and must meet factory specs. They must be "car audio
amplifiers designed to be powered from a car's electrical system."
8. Failure of an amp (this includes thermal shutdown) during the test
will require that the test be repeated after repair or replacement or
cooling of the amp. This means that the entire test session will have
to be repeated.
9. The amps will not be overloaded during the session from either a
voltage or current requirement.
10. To save time the listener will have to pass a quick 8 trial
session to qualify for the extended 2 session test for the money
prize. Any 2 amps can be used for this
test. Passing this qualifying test will require at least 6 out of 8
correct answers.
11. The amplifier power up and/or power down sequence will not be
acceptable for comparison. (The turn on/off noises of some amplifiers
would give it away.)
12. Although anyone is welcome to take the test, only subjects
employed in the car audio industry or Car Sound subscribers are
eligible for the $10,000.00 prize.
13. Cost to take the test is $100.00. $300.00 for people representing
companies. Payable in advance, scheduled appointments only. Done
correctly the test takes several hours and I don't have the time if
you aren't serious.
* Twelve correct responses in a row is certainly a lot of correct
listening but $10,000 is also a lot of money for a few hours of easy
listening. The way people describe the differences is that they are
like night and day. I would certainly not have any trouble choosing
between an apple and an orange 12 times in a row. When compared fairly
I believe the differences in amps are much too small to audibly detect
and certainly too small to pay large sums of extra money for. If I am
wrong someone should be able to carefully take this test and win my
money. Even if I am right, if enough people take the test eventually
someone will take my money due to random chance. This is the reason
for the large sample requirement. If you feel that you can easily pass
this test but 12 sequences will give you "listening fatigue" I am
willing to modify the requirements. Since the way it is being offered
is a challenge and only my money is at risk I am willing to let a
confident challenger "put his money where his ears are". If we are
willing to make this a bet instead of a challenge, I am willing to
drop 1 sequence for every thousand dollars put up by the challenger
against my money. This would mean:
____My___________ _ _Your________Trails Required to win__
$10,000 to $0 = 12 Tries
$9,000 to $1,000 = 11 Tries
$8,000 to $2,000 = 10 Tries
$7,000 to $3,000 = 9 Tries
$6,000 to $4,000 = 8 Tries
$5,000 to $5,000 = 7 Tries
$4,000 to $6,000 = 6 Tries
I will not do the test with less than 6 trails. It would be
statistically meaningless and reduce the challenge to mere gambling.
Lasse
> audio? Fair enough, I suppose...certainly limits the number of amps
> which fit the criteria of the contention though.
I found some more interesting info on Clarks Amp Challenge from:
http://www.talkaudio.co.uk/vbb/showthread.php?s=&threadid=18815
Summary: Home/pro/car/tube/solid state amps are all OK.
However, just from curiosity: Why would it be relevant to compare
home and pro amps in this context? I mean do people here in RAHE
regularly compare home vs. pro amps when buying new gear? If not,
then where's the beef?
Lasse Ukkonen
Bob Marcus
> > You said that one sides contends that All Amps Sound the Same,
> > which is not the case. I'm trying to get a more careful
> > claim out of you.
> >
>
> If it's not the case, then I've been getting a misrepresentation of
> the contentions from posts I've read here on RAHE.
"Getting a misrepresentation of"? You mean, "misreading".
> (Until I started
> reading this ng, I'd never heard *anyone* claim all power amps sound
> the same, much less offer money to anyone who could pick them out
> blind.)
And you still haven't heard anyone claim that.
> Have I misunderstood the basic premise of (for lack of a
> better word) The Objectivists, that all competantly-designed power
> amplifiers are sonically indistinguishable?
Almost: All competently designed amps operating within their design
limits (i.e., not driven into excessive clipping) appear to be audibly
indistinguishable. One key assumption here is that a competently
designed amp will have a flat frequency response. Hence Nousaine's
100, 1K, 10K level-matching criterion.
bob
Nousaine
...snip.....
>What is seriously lacking in this discussion isn't a definitve experiment
>showing that all competent amplifiers sound the same BUT a definitive level
>matched blind comparison experiment that shows that ANY of them actually DO.
I meant to say that "...that ANY of them actually DO sound DIFFERENT!"
Chung
Here's where you are wrong. The listener listens to the amp, *NOT* the
amp with the feedback loop open. You can have amps with vastly different
open loop responses, but if the closed-loop response differences are
beneath audible thresholds, then the amps will sound the same. (For
example, there are dozens of op amps that can be used in the signal
path, all with different open-loop responses. But many of them will
sound identical if used properly.)
To say that the sound is influenced by the open-loop response is saying
very little of substance. You might as well say that the sound is
influenced by the power supply, the choice of transistors, the choice of
resistors and capacitors, etc. You surely would not say that you are
listening to the power supply now, would you?
Buster Mudd
>
> How did you move from "all competantly (sic)-designed power amplifiers
> are sonically indistinguishable" to "All Amps Sound the Same"?
>
I trust your point is that the difference between those two statements
is the "competantly designed" qualifier? Otherwise I fail to see how
there is a meaningful difference between "All Amps Are Sonically
Indistinguishable" and "All Amps Sound The Same".
>
> The 'conditions and caveats' simply excude amps with
> non-flat frequency response, and constrain the outputs to below the
> clipping level of the least powerful amp in the comparison. You have a
> problem with those simple and obvious pre-conditions?
>
I just find those conditions unrealistic for some comparisons. I've
encountered a few amplifiers that have a hard time meeting those
pre-conditions in their normal intended use...yet despite that they
have found widespread use, regardless of whether or not one wants to
consider them competantly designed. These amps are audibly quite
distinguishable from other (ostensibly more competantly designed) amps
*when compared in real-world situations*. Eg., it's pointless to say
that a Peavey CS800 is sonically indistinguishable from ____________
(insert name of nearly any other amp here) "when not driven into
clipping" because a Peavey CS800 is realistically incapable of
fulfilling its intended purpose without going into clipping. I'm not
saying that isn't incompetant design, but I am saying that it would
surprise me if someone couldn't hear the difference if another model
power amp were swapped into the same system.
> You think this
> affects 'slam', 'inner detail', 'rhythm and pace', 'ambience',
> 'microdynamics', and all the other high end bullshit terms?
I think it affects the practicality of the comparison.
(BTW, can someone explain to me what audiophiles mean by "pace" or
"rhythm" when describing a component?)
Ban
What is an armchair speculation is what *you* are stating. I know what you
have in mind. When a sudden pulse comes, the feedback chain inside the amp
couples the output back to the input. Because of the delay from input to
output, the correction will not work immediately, so the first microseconds
the response will be too high. This is wrong.
The input signal can not slew so fast that this will happen, we have a
band-limited input from all of our signal sources. The CD-player will give
out a signal with a slew-rate limited by the reconstruction filter. This
signal will be looking smooth, not like the step diagrams drawn by some
High-End morons. The same is true for the catridge signal. The mass of the
needle assembly will not accelerate faster then a certain limit. Any
competent amp can easily follow those signals with a neglegible overshoot,
no matter what its open loop response might be. And even if the amp wouldn't
be able to do that, the treble speaker couldn't follow so fast anyway. The
additional frequency components are mainly above the human hearing.
Much more annoying and audible were incompetent filters used in
D/A-converters with ringing reconstruction filters or missing filters, which
lead to aliasing. This creates additional frequencies not found in the
original signal and sounds "scratchy". Our ears are sensitive for that, as
the frequencies might well be in the most sensitive area of our
ears(2-3kHz). But the amplifier again has nothing to do with it, it just
amplifies the crap at its input.
--
ciao Ban
Bordighera, Italy
B&D
<chun...@covad.net> wrote:
> B&D wrote:
>> On 10/6/04 7:43 PM, in article ck1vv...@news4.newsguy.com, "Chung"
>> <chun...@covad.net> wrote:
>>
>>>> It should be if you were to run a series of transient events through the
>>>> amp
>>>> and look at the phase and amplitude response. I have no idea how one would
>>>> do a sufficiently complex set of tests in closed loop format to see -
>>>> perhaps a series of triangle waves or square waves? I don't know.
>>>
>>> The problem you have is that you keep trying to refer to the open-loop
>>> response, when the listener (or tester) is hearing the closed-loop
>>> response. The open-loop response is irrelevant to the listener. Why
>>> would the listener be interested to finding out what the open-loop
>>> response is (other than academic curiosity)?
>>
>> The listener will hear both the open loop and closed loop response. In the
>> steady state condition you will hear the closed loop response. In
>> transients the sound will be influenced by the open loop response.
>
> Here's where you are wrong. The listener listens to the amp, *NOT* the
> amp with the feedback loop open. You can have amps with vastly different
> open loop responses, but if the closed-loop response differences are
> beneath audible thresholds, then the amps will sound the same. (For
> example, there are dozens of op amps that can be used in the signal
> path, all with different open-loop responses. But many of them will
> sound identical if used properly.)
That isn't true at all.
>
> To say that the sound is influenced by the open-loop response is saying
> very little of substance. You might as well say that the sound is
> influenced by the power supply, the choice of transistors, the choice of
> resistors and capacitors, etc. You surely would not say that you are
> listening to the power supply now, would you?
I doubt you mind can be changed at this point, if it ever would be.
The open loop response of an amplifier is critical to the performance of the
entire amp - and its response does influence the sound of transients. As
someone who designs amplifiers in general, I have seen it and I am currently
working on a upgrade to an existing design where the performance is to
change the feedback to allow faster rise times and load changes in a
reliable manner.
One "listens" to am amplifier in its entirely - both the open and closed
loop response. A previous poster mentioned a source slew rate - and that is
important to keeping the amp under control - and I did mention "sufficiently
slow loop" will be audible - and I suspect most amps do this.
I am not wrong at all, but in all the eagerness to declare it so, it appears
Stewart Pinkerton
>To say that the sound is influenced by the open-loop response is saying
>very little of substance. You might as well say that the sound is
>influenced by the power supply, the choice of transistors, the choice of
>resistors and capacitors, etc. You surely would not say that you are
>listening to the power supply now, would you?
You are. An amplifier is basically just a variable valve that connects
the power supply to the speaker. Hence the importance of good power
supplies.
B&D
> Here's where you are wrong. The listener listens to the amp, *NOT* the
> amp with the feedback loop open. You can have amps with vastly different
> open loop responses, but if the closed-loop response differences are
> beneath audible thresholds, then the amps will sound the same. (For
> example, there are dozens of op amps that can be used in the signal
> path, all with different open-loop responses. But many of them will
> sound identical if used properly.)
Put a capacitor as the feedback on the op amp - and put in a rising edge of
a square wave and note the transient and long term response. Do it with a
rising edge of various input signals.
Do it with a variety of capacitors and rising times and you will see that
the initial response and final response are different. THIS is a very
simplified example of what I am talking about (though not 100% accurate -
just to illustrate my point).
Have you ever used op amps?
B&D
"jjn...@sonic.net" <jjn...@sonic.net> wrote:
>> The listener will hear both the open loop and closed loop response. In the
>> steady state condition you will hear the closed loop response. In
>> transients the sound will be influenced by the open loop response.
>
> Sure, if you're referring to obsolete dreck designs like a 741 op amp and
> the like.
>
> If one can hear this going on then that amplifier cannot be said to be
> 'nominally competent'. What news!
>
> Why worry about it these days?
I am not particularly worried about it myself, but when you design an
amplifier using global feedback, you do need to take this into account - not
to mention that a lot of feedback can make an amplifier less stable as well.
The group delay of the signal chain in the amplifier itself, plus the speed
of the feedback loop times 10 should be around the time the unit should be
more or less the steady state response. For a digital control loop (a lot
of which I use for some of the other items I work with) providing global
feedback, the rule of thumb is 10 x the sample rate.
Bob Marcus
> Stewart Pinkerton <pat...@dircon.co.uk> wrote in message news:<ck57k...@news2.newsguy.com>...
> >
> > How did you move from "all competantly (sic)-designed power amplifiers
> > are sonically indistinguishable" to "All Amps Sound the Same"?
> >
>
> I trust your point is that the difference between those two statements
> is the "competantly designed" qualifier?
Bingo!
> Otherwise I fail to see how
> there is a meaningful difference between "All Amps Are Sonically
> Indistinguishable" and "All Amps Sound The Same".
>
> >
> > The 'conditions and caveats' simply excude amps with
> > non-flat frequency response, and constrain the outputs to below the
> > clipping level of the least powerful amp in the comparison. You have a
> > problem with those simple and obvious pre-conditions?
> >
>
> I just find those conditions unrealistic for some comparisons.
What's unrealistic is your expectation that anyone would bet on the
inaudibility of amps that *don't* meet those conditions.
> I've
> encountered a few amplifiers that have a hard time meeting those
> pre-conditions in their normal intended use...yet despite that they
> have found widespread use, regardless of whether or not one wants to
> consider them competantly designed.
I think the problem here is that we've got two distinct definitions of
"competent" here. What High-End Objectivists mean is that it's quite
possible to design an amp that's powerful enough to drive whatever
load you're trying to drive with low distortion and flat FR, and that
there's really no excuse not to design an amp that way for home audio
reproduction.
Of course, some people want distorted sound, especially on the pro
side. (Some people may want distorted sound on their home systems,
too, although it's never described that way. They call it, "more like
live music"!) An amp that's *designed* to clip, because clipping
distortion is part of the sound you want, is competently designed for
*that* purpose. But when we say amps aren't distinguishable, those
aren't the amps we're talking about, which is why those pre-conditions
you object to are there.
> These amps are audibly quite
> distinguishable from other (ostensibly more competantly designed) amps
> *when compared in real-world situations*. Eg., it's pointless to say
> that a Peavey CS800 is sonically indistinguishable from ____________
> (insert name of nearly any other amp here) "when not driven into
> clipping" because a Peavey CS800 is realistically incapable of
> fulfilling its intended purpose without going into clipping. I'm not
> saying that isn't incompetant design, but I am saying that it would
> surprise me if someone couldn't hear the difference if another model
> power amp were swapped into the same system.
And it would surprise the rest of us, which is why no one's betting
that way.
>
> > You think this
> > affects 'slam', 'inner detail', 'rhythm and pace', 'ambience',
> > 'microdynamics', and all the other high end bullshit terms?
>
> I think it affects the practicality of the comparison.
>
> (BTW, can someone explain to me what audiophiles mean by "pace" or
> "rhythm" when describing a component?)
Those terms are used by people who don't understand the difference
between a musical performance and the reproduction of a musical
performance, and so ascribe attributes of performance to reproduction.
In the context of reproduction, they mean nothing, or they mean
whatever you want them to mean. Take your pick.
bob
B&D
Pinkerton" <pat...@dircon.co.uk> wrote:
Transients in this case would be something like a plucked string of a
guitar, etc.
But your point is true - to use feedback properly, you MUST take slew rate
into account and make sure the input cannot exceed the speed of the feedback
and delay - probably by a factor of 10 or more to make the sound less or
inaudible.
Absorbing the leading edge of the transients through filtration or other
means, you have to be careful as well since you are removing and altering
the signal in a benign manner.
Stewart Pinkerton
>On 10/8/04 11:20 AM, in article ck6b7...@news3.newsguy.com, "Chung"
><chun...@covad.net> wrote:
>> The listener listens to the amp, *NOT* the
>> amp with the feedback loop open. You can have amps with vastly different
>> open loop responses, but if the closed-loop response differences are
>> beneath audible thresholds, then the amps will sound the same. (For
>> example, there are dozens of op amps that can be used in the signal
>> path, all with different open-loop responses. But many of them will
>> sound identical if used properly.)
>
>That isn't true at all.
Yes it is, and proveably so. Do you have any evidence beyond mere
assertion, for your opinion?
>The open loop response of an amplifier is critical to the performance of the
>entire amp - and its response does influence the sound of transients. As
>someone who designs amplifiers in general, I have seen it and I am currently
>working on a upgrade to an existing design where the performance is to
>change the feedback to allow faster rise times and load changes in a
>reliable manner.
As someone else who has been designing amplifiers - for about thirty
years now - I agree that it is *preferable* to start with a reasonably
linear open loop response. However, it is *not* essential, for sonic
transparency. BTW, how do you propose to change the *feedback* to
improve transient performance?
>One "listens" to am amplifier in its entirely - both the open and closed
>loop response.
A well-designed amplifier will not allow the feeback loop to lose
control. Hence, you will *only* hear the closed loop response.
> A previous poster mentioned a source slew rate - and that is
>important to keeping the amp under control - and I did mention "sufficiently
>slow loop" will be audible - and I suspect most amps do this.
It is sufficient to place a filter at the input, which will not allow
slew rate limiting at full output. Crude, but effective. Your
'suspicion' is irrelevant, unless you can *demonstrate* the existence
of this effect in a real-world amplifier.