HI-FI SPEAKERS
Y Conyers
I am intending to upgrade the PETERSONS that I presently have.
The Amp I have is a Yamaha Surround Sound AVX-100.
The speakers I have been looking at are:
1.BOSE ACOUSTIMASS-5 series 11
2.WHARFDALE SATTELLITES
The BOSE are twice the price of the Wharfdales, which are on a sale presently.
I am wondering if I am paying all that extra money because of the BOSE name.
The Wharfdales are made in England.
Also what is the difference between a SUB_WOOFER and a BASE DRIVER
Please reply to this group or email me direct
Any help would be appreciated.
Thanks
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BYRNES,Graham
> Is there anyone out there who can give me some advice on Speakers.
> I am intending to upgrade the PETERSONS that I presently have.
> The Amp I have is a Yamaha Surround Sound AVX-100.
> The speakers I have been looking at are:
> 1.BOSE ACOUSTIMASS-5 series 11
> 2.WHARFDALE SATTELLITES
> The BOSE are twice the price of the Wharfdales, which are on a sale presently.
> I am wondering if I am paying all that extra money because of the BOSE name.
> The Wharfdales are made in England.
> Also what is the difference between a SUB_WOOFER and a BASE DRIVER
> Please reply to this group or email me direct
> Any help would be appreciated.
There is a general opinion about that Bose systems are overpriced, over
marketed and underbuilt, even in the US market where they ought to be cheaper.
One of the English hi-fi mags recently tested a bunch of satellite systems,
the general conclusion was that they were all a bit suss, and better value
could be had from small full range two way speakers.
All the above is hearsay, obviously.
A base driver is usually built into the main speaker, and typically
operates upto 800 or even out to 3000Hz (ie top of the piano keyboard)
Subwoofer tend to be separate and only go to about 200Hz. Because
of this they can use a resonator type design to get good bass from
small (cheap) drivers. The downside is that although the bass is loud
there tends to be major phase distortion (ie it takes a while to get
the resonator resonating, and it doesn't stop right away either). So
everything gets a bit muddy.
Depends on the sort of listening you do, really.
Have fun...take some CD's and go listen to some samples. To add to the names
suggested elsewhere, look for VAF speakers. I heard them in Adelaide
when I was there, don't know about distribution elsewhere.
Graham B
PS apropos de rien, c'est un nom francais, Conyers? Je m'excuse.
BSD_G...@vd.seqeb.gov.au
> The speakers I have been looking at are:
> 1.BOSE ACOUSTIMASS-5 series 11
> 2.WHARFDALE SATTELLITES
> The BOSE are twice the price of the Wharfdales, which are on a sale presently.
> I am wondering if I am paying all that extra money because of the BOSE name.
Can u give us some more info on the Wharfdales? Are they the new 2-way closed
box system? Or are they a subwoofer system like the Bose?
I think the issue to keep in mind with the type of subwoofer mentioned above,
they're called passive because they have no internal amplifier driving them, is
that your amp must have the grunt to drive them. I'm not that familiar with
your amp. What is its rating for the front channels?
Another issue with subwoofers is that they have a narrow bandpass which is a
bit of a compromise and they are in a vented box. Associated with the latter is
a hump in the response, basically instead of being a flat response, which is
the ideal, there is a bump. This effects the bass which of course u are trying
to listen to. (I might add u don't get this hump in an optimum design, but I
know of no manufacturer who builds their subwoofer this way. Basically because
the box is too big!)
This translates, in listening, to a muddied or blurred bass that is not as fast
in its bass response to that of a conventional speaker. Well that's my opinion,
however humble that maybe!
If u are thinking of spending the sort of money that the Bose system would
cost, I'd suggest looking at a two-way system like an InterdYn BT1, Dynaudio
Image 2 or (if money can stretch that far) an Image 3, or a Whatmough model
201. They're all Australian speakers and represent excellent value for money.
Should u wish to stick with Wharfdales, they have a new closed box design which
is quite impressive. I'll try & find out the model number, don't have it at the
moment.
I'd be interested to see what others say about subwoofers, but I think that the
bass from a good conventional system is more accurate and faster. Have a listen
& let us know what u think.
> Also what is the difference between a SUB_WOOFER and a BASE DRIVER
Essentially a subwoofer is in a box for itself & allows placement in out of the
way places. A base driver is the woofer element of a conventional speaker
system.
> Thanks
That's ok.
Gordon Clarke, email: bsd_g...@seqeb.gov.au
S.E.Q.E.B., Brisbane
John Mazzocchi
>
> This translates, in listening, to a muddied or blurred bass that is not as fast
> in its bass response to that of a conventional speaker. Well that's my opinion,
> however humble that maybe!
I tend to agree with you; in my experience small (definitely under 8") drivers sound
faster and more accurate. A subwoofer available a few years ago made by Audio-Pro
would use two 6"(?) drivers in a push-pull configuration so that the rear driver
would "cancel out" nonlinearities (in phase? I can't exactly remember their claims)
of the front driver. Other speaker manufacturers (e.g. Dali) have also used this
principle.
> I'd be interested to see what others say about subwoofers, but I think that the
> bass from a good conventional system is more accurate and faster. Have a listen
> & let us know what u think.
I agree here - large (say 15" and above) woofers sound terrible to me. Infinity
(and presumably Watkins) used to make the Infinity/Watkins 15" dual voice-coil
woofer; my guess is the dual voice-coils were used to improve the speed of the driver.
> > Also what is the difference between a SUB_WOOFER and a BASE DRIVER
>
> Essentially a subwoofer is in a box for itself & allows placement in out of the
> way places. A base driver is the woofer element of a conventional speaker
> system.
Absolutely correct, but before it propagates any further -it's a *bass* driver, not a
base driver (although some of them *are* pretty poor :-)
Cheers, John.
BYRNES,Graham
> faster and more accurate. A subwoofer available a few years ago made by Audio-Pro
> would use two 6"(?) drivers in a push-pull configuration so that the rear driver
> would "cancel out" nonlinearities (in phase? I can't exactly remember their claims)
> of the front driver. Other speaker manufacturers (e.g. Dali) have also used this
> principle.
The idea of push-pull drivers is the same as push pull amp output stuges etc:
2nd harmonic distortion arises when the driver behaves differently going
forward to going back. If they ar back to back, one is going in each direction,
so the result cancels out: No 2nd harmonic distortion (in principle8-)).
The problem is that the 2 only move the same amount of air per unit
displacement as a single driver the same size, so they have to move a long way.
That tends to cause distortion, as the magnetic field is not uniform at the
extremes of excursion. Unfortuately it happens at both extremes, so it
is odd order and doesn't cancel /8-(. To limit the excursion, you have to
use a bandpass resonator type thingy, which causes:
>
> > I'd be interested to see what others say about subwoofers, but I think that the
> > bass from a good conventional system is more accurate and faster. Have a listen
> > & let us know what u think.
>
ie phase inaccuracy due to the lousy transient response of high order
filters. For a Butterworth (max flat) filter, the phase change is 45n degrees
at the -3dB point, where n is the order of the filter.
A sealed box is 2nd order, a conventional bass reflex is 4th, multi ported
subwoofing beasts are 6th or 8th. That means an 8th order filter has a phase
change of 360 degrees at -3dB, or a full cycle. At low frequencies that
is all the more significant: at 20Hz, it is 5ms, so the source appears to
be displaced by the distance sound travels in that time, ie about 5ft (sorry,
its easier to remember 1ft/ms than to work out 345/200metres). That dont
do wonders for your imaging. Also, I suspect Bose et al cheat by using
a very non-butterworth alignment to get more output (ie a real live
Helmholtz resonator). Which makes things much worse.
> I agree here - large (say 15" and above) woofers sound terrible to me. Infinity
> (and presumably Watkins) used to make the Infinity/Watkins 15" dual voice-coil
> woofer; my guess is the dual voice-coils were used to improve the speed of the driver.
Usually because the cone is too flexible. If its big, it better be strong.
If its strong, it costs plenty. If it's big and strong, it costs too much.
(Hence the brand name, yes?)
I use 2 separate 10" drivers in sealed boxes, with active equalisation:
that helps with the phase response as well. The main speakers are left alone
so they don't have to suffer nasty filter circuitry. It sounds pretty good,
goes down to 16Hz -3dB. But it won't produce the really huge SPL's you
can get from vents and so on.
Graham
Chris O'Neill
MAT...@LURE.LATROBE.EDU.AU (BYRNES,Graham) writes:
>In <1992Jun17.0...@mel.dit.csiro.au> jo...@shark.mel.dit.csiro.au
writes:
>> I agree here - large (say 15" and above) woofers sound terrible to me.
Infinity
>> (and presumably Watkins) used to make the Infinity/Watkins 15" dual
voice-coil
>> woofer; my guess is the dual voice-coils were used to improve the speed of
the driver.
>
>Usually because the cone is too flexible. If its big, it better be strong.
>If its strong, it costs plenty. If it's big and strong, it costs too much.
>(Hence the brand name, yes?)
Yes it's interesting that the cost of large woofers increases significantly
with their size (while the high frequency performance degrades). So much so
that there is no "economy of scale" occurring. e.g. one well known driver
manufacturer produces a paper cone 12" that costs about the same as two of
their plastic cone 8" drivers. The two 8" drivers can produce about the same
power at low frequencies as the 12" but sound a lot better at high frequencies.
The high frequency (>300 hz) performance of a bass driver depends on the
frequency at which cone break-up (standing wave vibrations) occurs and the
behaviour of break-up when it occurs. In general, the larger the cone, the
lower the frequency at which break-up occurs. A good 12" paper cone whould
have a lower break-up frequency of around 400 hz while a good plastic 8" cone
begins break-up at something like 800-1000 hz. Not only do large cones begin
break-up at a lower frequency, but their break-up usually sounds worse. I
haven't heard of an economical, 12" driver suitable for crossover frequencies
above 200 hz. It seems that driver manufacturers don't bother trying to
develop good sounding drivers larger than 10".
>I use 2 separate 10" drivers in sealed boxes, with active equalisation:
>that helps with the phase response as well. The main speakers are left alone
>so they don't have to suffer nasty filter circuitry. It sounds pretty good,
>goes down to 16Hz -3dB. But it won't produce the really huge SPL's you
>can get from vents and so on.
Chris O'Neill
James Scott
....stuff deleted
>The high frequency (>300 hz) performance of a bass driver depends on the
>frequency at which cone break-up (standing wave vibrations) occurs and the
>behaviour of break-up when it occurs. In general, the larger the cone, the
>lower the frequency at which break-up occurs. A good 12" paper cone whould
>have a lower break-up frequency of around 400 hz while a good plastic 8" cone
>begins break-up at something like 800-1000 hz. Not only do large cones begin
>break-up at a lower frequency, but their break-up usually sounds worse. I
>haven't heard of an economical, 12" driver suitable for crossover frequencies
>above 200 hz. It seems that driver manufacturers don't bother trying to
>develop good sounding drivers larger than 10".
As you have said, the onset of cone breakup depends upon the diameter of the
diaphragm. This is a result of the physics of the piston radiator and cannot
be helped. Therefore, I can't see what your last comment above was trying to
say. I think the main reason to go to a larger cone diameter is to get good
efficiency at the lower frequencies, and also to get a driver with a low
self resonant frequency. Q factor of course is also very important in
determining the enclosure dimensions you need to get a good (whatever that
means:-) low frequency response.
>Chris O'Neill
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Chris O'Neill
(James Scott) writes:
>c.on...@trl.oz.au (Chris O'Neill) writes:
>
>....stuff deleted
>
>>The high frequency (>300 hz) performance of a bass driver depends on the
>>frequency at which cone break-up (standing wave vibrations) occurs and the
>>behaviour of break-up when it occurs. In general, the larger the cone, the
>>lower the frequency at which break-up occurs. A good 12" paper cone whould
>>have a lower break-up frequency of around 400 hz while a good plastic 8" cone
>>begins break-up at something like 800-1000 hz. Not only do large cones begin
>>break-up at a lower frequency, but their break-up usually sounds worse. I
>>haven't heard of an economical, 12" driver suitable for crossover frequencies
>>above 200 hz. It seems that driver manufacturers don't bother trying to
>>develop good sounding drivers larger than 10".
>
>As you have said, the onset of cone breakup depends upon the diameter of the
>diaphragm. This is a result of the physics of the piston radiator and cannot
>be helped. Therefore, I can't see what your last comment above was trying to
>say.
I'm saying that usually a pair of 8" drivers is a much better choice than a 12"
driver (as I implied from an earlier statement comparing a 12" with two 8"
drivers), i.e. for the same cost you get a pair of drivers with the same bass
performance and a much better performance above 400 hz, i.e. economy of scale
arguments imply that the 12" should be more economical for producing bass than
two 8" drivers but in this case economy of scale does not occur.
> I think the main reason to go to a larger cone diameter is to get good
>efficiency at the lower frequencies,
No, the reason for having larger cone area is so that you can generate more
acoustic power at low frequencies ( <100 hz) for a given amount of cone
displacement which determines the doppler intermodulation distortion and other
distortions.
Efficiency depends on a lot of variables besides cone area. Increasing cone
area (for fixed cone mass to increase the efficiency) has the disadvantage
(among others) that enclosure volume must increase in proportion with cone area
to maintain the same system lower resonance frequency.
> and also to get a driver with a low
>self resonant frequency.
This depends on the cone suspension compliance and the cone mass. With high
performance drivers the compliance is chosen to be significantly greater than
the compliance of the air in the enclosure sizes that it is intended for.
Hence to get an appropriate self resonant frequency, designers choose the
appropriate compliance after the cone mass has been determined. (This normally
means that high performance drivers have a lower resonance frequency than lower
performance drivers of the same size.)
> Q factor of course is also very important in
>determining the enclosure dimensions you need to get a good (whatever that
>means:-) low frequency response.
For a given enclosure volume and driver the Q can be increased by using bass
reflex design. High performance drivers have a low infinite baffle Q. So if
you want to use a large enclosure (to get a low system resonance) you need to
use a bass reflex design to get a system Q that isn't too low.
Of course, these and other issues are dealt with in references on the subject.
>+ James Scott e-mail: rc...@quokka.co.rmit.oz.AU
+
Chris O'Neill
Telecom Research Labs
BYRNES,Graham
> reflex design. High performance drivers have a low infinite baffle Q. So if
> you want to use a large enclosure (to get a low system resonance) you need to
> use a bass reflex design to get a system Q that isn't too low.
Just a slight quibble: the Q of a good driver depends on its intended
application. If it is meant for a reflex design, it will have a low (.25-.4)
Q. If it is meant for infinite baffle, it will be higher.
Remember the defn of Q: The driver satisfies
x"(t)+wx'(t)+w^2x(t)=f(t),
-----
Q
where x is the displacement and w is the res freq. fm is the driving force.
So if you increase w by making the cabinet *smaller*, then Q will get bigger.
Hence starting with a low Q driver in an inf baffle alignment requires a small
box. If you want a large box and low Q, you have to raise Q by other methods.
1/Qt=1/Qe+1/Qm, with the first term dominant, so you can increase Q by
increasing Qe, which is proportional to the series resistance. Ie, stick
in a resistor.
>
> Of course, these and other issues are dealt with in references on the subject.
>
Graham B
Chris O'Neill
MAT...@LURE.LATROBE.EDU.AU (BYRNES,Graham) writes:
>In <1992Jun23....@trl.oz.au> c.on...@trl.oz.au writes:
>> reflex design. High performance drivers have a low infinite baffle Q. So
if
>> you want to use a large enclosure (to get a low system resonance) you need
to
>> use a bass reflex design to get a system Q that isn't too low.
Just to clarify my terminology on "infinite baffle", I don't like using the
term "infinite baffle" to describe a sealed box of finite size. By infinite
baffle I meant a real infinite baffle, i.e. an infinite plane with the driver
mounted in it. Yes, I'll have to be more careful about using the term
"infinite baffle", even though I think the common usage is a misnomer.
>Just a slight quibble: the Q of a good driver depends on its intended
>application. If it is meant for a reflex design, it will have a low (.25-.4)
>Q.
Although you can use it in a sealed box of appropriate size for the system Q
that you require, if you want to.
> If it is meant for infinite baffle, it will be higher.
>
>Remember the defn of Q: The driver satisfies
>x"(t)+wx'(t)+w^2x(t)=f(t),
> -----
> Q
>where x is the displacement and w is the res freq. fm is the driving force.
>
>So if you increase w by making the cabinet *smaller*, then Q will get bigger.
>Hence starting with a low Q driver in an inf baffle alignment requires a small
>box. If you want a large box and low Q, you have to raise Q by other methods.
Should read high
>1/Qt=1/Qe+1/Qm, with the first term dominant, so you can increase Q by
>increasing Qe, which is proportional to the series resistance. Ie, stick
>in a resistor.
>>
>> Of course, these and other issues are dealt with in references on the
subject.
>>
>Graham B
>
Chris O'Neill
Russell Day
My UREI 813s use Altec 604-8G units for their midrange/tweeter. This is a
15" high-grade driver with a coaxial horn. Both drivers in the 604-8G
have enormous magnets. There is also another 15" driver for the low stuff.
The crossover is an E.M.Long Time-Aligned (tm, of course) unit.
The cabinets are huge - about 38" high by 30" wide by 22" deep.
These are not PA speakers (they are too heavy!). They were designed
as high fidelity monitors for studio applications. Recommended
maximum amp size is 200 watts, although I drive them using a Luxman
with a 60WRMS claimed output. Most of the time they just idle although
they sound marvy at all power levels.
They were (and possibly still are) used extensively as studio monitors -
I know that Albert's in Sydney had about 8 sets of them, two for each offour
studios (a pair in the control room, and a pair in the studio itself.
I say this to reinforce the notion that they are a very high fidelity
speaker - so there are no problems introduced by the 15" midrange. I
believe they were (are?) used extensively during mixing because of
their accuracy.
The overall sound is excellent, even though they are 10 years old and probably
need a recone. I listen to a lot of classical music, where the
midrange and high freqs are critical - Absolutely superb.
---------------------------------------------------------------------
QUESTION!
The bass response of my pair is a bit tame. This is certainly
because I bought kits in SanFrisco and the cabinets were
built in Australia. I believe the boxes are ok (each has 24 feet of
4x2 as internal bracing, and they are built of 1" HD chip with a 6mm
5ply laminate on the outside) - more or less the same as the original
UREI box that I measured up in the States. I expect that the damping
material is the problem (a packet of R4.0 pink bats, in fact - any
suggestions about a replacement stuffing - Rockwool perhaps?) I am
not a bass freak - they have been this way for 10 years, but maybe now
is the time to fix them?
---------------------------------------------------------------------
I priced a new set from Jands in 1990, they said around $13,000 per pair,
plus tax. Good Grief. And the new ones have JBL drivers. Bummer.
Has anyone else seen a 15" midrange in a high quality system?