Installing internal microphones without feedback.
Viktor
I play in a rockband. Very loud - and of course I have a lot of
feedback-problems - also in rehearsal-studio.
My former accordion was a Hohner Bravo III 96, where I installed
THOMANN ACM-01 accordion pickup system. Cheap, but worked quite well:
http://www.thomann.de/gb/thomann_acm01.htm
I put some leather inside the case of the accordion to take away some
of the resonance, which I think helped a little regarding feedback.
Then I fell in love with a TIGER Combo´cordion from the sixties, and
bought it through EBAY:
Treble-side:
http://www.flickr.com/photos/31544092@N06/3704893546/in/set-72157621052310113/
Bass/Chorus-side:
http://www.flickr.com/photos/31544092@N06/3704083637/in/set-72157621052310113/
It came with an original crystal(?) microphone placed in the bellows.
Unfortunately the amplified sound was very sharp, and lots of
feedback.
Therefore I went to an accordion-dealer, and he suggested the
Microtech/Sennheiser MT-04 system, which he installed.
In the following pictures you can se how the system was installed.
Inside the treble side:
http://www.flickr.com/photos/31544092@N06/3704084089/in/set-72157621052310113/
Inside the bass/chorus side:
http://www.flickr.com/photos/31544092@N06/3704083261/in/set-72157621052310113/
I still have feedback-issues. Even though the sound is much better,
the Thomann system actually worked better regarding feedback. I also
experience a phase-problem, since the treble-side strangely has more
feedback when the bass/chorus-side is turned down.
Has my accordion dealer put the mike correctly on the bass/chorus-
side?
Close-up in the bass/chorus-side
http://www.flickr.com/photos/31544092@N06/3704082337/in/set-72157621052310113/
Has anyone here got experience with installing internal microphones?
Is it maybe an idea to put a piece of foam weatherstrip(?) under the
circuit board to act as a sound damper, as John C. writes here:
http://groups.google.com/group/rec.music.makers.squeezebox/msg/7b99a8cfe97abb6b?hl=en&dmode=source
Any other suggestions are greatly appreciated!!!
Viktor (Copenhagen, Denmark)
john
Your current microphones are not good enough.
If you wish, contact Limex Music in Austria or Limex Dealer in Nederland.
The Limex microphone system will solve your current problem.
John
http://www.johnsaccordionservice.com/
"Viktor" <vik...@itu.dk> wrote in message
news:1b9808d1-7ed4-4ea3...@c36g2000yqn.googlegroups.com...
Len Killick
to seeing the two volume controls next to each other; they are usually
placed each side of the register switches, but I wouldn't expect that
to cause any problem (but just puzzled about your comment about the
effect on the treble of turning down the bass).
There's also usually no problem with feedback, especially with the
Sennheiser capsules. I've seen a lot of them in instruments and they
don't have feedback problems. Perhaps you need to look at your
complete sound system - I always set mine up with minimal gain (i.e.
low volume setting) on the accordeon and let the power amp do the
work, if you have the accordeon volume regulators set up high the
capsules might well pick up all sorts of external sounds.
I don't agree with John's comment that these microphones are not good
enough, any microphone will have feedback probelms if the complete
system is not set up correctly.
On Jul 9, 11:18 pm, Viktor <vik...@itu.dk> wrote:
> Hello! First time for me here.
>
> I play in a rockband. Very loud - and of course I have a lot of
> feedback-problems - also in rehearsal-studio.
>
> My former accordion was a Hohner Bravo III 96, where I installed
> THOMANN ACM-01 accordion pickup system. Cheap, but worked quite well:http://www.thomann.de/gb/thomann_acm01.htm
>
> I put some leather inside the case of the accordion to take away some
> of the resonance, which I think helped a little regarding feedback.
>
> Then I fell in love with a TIGER Combo´cordion from the sixties, and
> bought it through EBAY:
> Treble-side:http://www.flickr.com/photos/31544092@N06/3704893546/in/set-721576210...
> Bass/Chorus-side:http://www.flickr.com/photos/31544092@N06/3704083637/in/set-721576210...
>
> It came with an original crystal(?) microphone placed in the bellows.
> Unfortunately the amplified sound was very sharp, and lots of
> feedback.
>
> Therefore I went to an accordion-dealer, and he suggested the
> Microtech/Sennheiser MT-04 system, which he installed.
>
> In the following pictures you can se how the system was installed.
>
> Inside the treble side:http://www.flickr.com/photos/31544092@N06/3704084089/in/set-721576210...
>
> Inside the bass/chorus side:http://www.flickr.com/photos/31544092@N06/3704083261/in/set-721576210...
>
> I still have feedback-issues. Even though the sound is much better,
> the Thomann system actually worked better regarding feedback. I also
> experience a phase-problem, since the treble-side strangely has more
> feedback when the bass/chorus-side is turned down.
>
> Has my accordion dealer put the mike correctly on the bass/chorus-
> side?
> Close-up in the bass/chorus-sidehttp://www.flickr.com/photos/31544092@N06/3704082337/in/set-721576210...
>
> Has anyone here got experience with installing internal microphones?
> Is it maybe an idea to put a piece of foam weatherstrip(?) under the
> circuit board to act as a sound damper, as John C. writes here:http://groups.google.com/group/rec.music.makers.squeezebox/msg/7b99a8...
Iam
I also disagree with John and agree with Len completely regarding the
Sennheiser caps (I also have the Microtech system) although I've never
used the Limex product. The only absolute solution would be to take
microphones completely out of the picture - (or put yourself in an
isolation box or buy a Roland V)
Ventura
welcome
i see you do know how to search the newsgroup archives...
use the keyword Sennheiser and you'll find our detailed
solutions from years ago... i have taken apart and reviewed
quite a few systems with results published here.
this system you have is available with either Sennheiser
elements, or cheaper generic elements
the closeup of your bass side does not look like the
Sennheiser element, which is smaller and shaped somewhat
like an old fashioned Watertower (like the Warner Bros.
cartoon image, if you've never seen one in real life)
amd a small hole in the center of the domed top
they may have changed in recent years, but if i were you
i would make damn sure you were given what you paid for
the Senn's are hypercardiod and resist feedback quite well
next, the manufacturer of the Tiger's is still in business,
shop's located now just south of Washington DC, if you
even need parts or service
third... you don't need treble response on the Bass,
so run in Stereo, turn your hi tone control all the way
left, turn the mid also 3/4 left, turn the low 1/4 right
on that channel input
4th... personally, i always put the 4th senn element
on the treble as well, jumper wire it to the long board,
and put something like a Shure Green Bullet element
on the Bass (large diaphram = low wind noise) mounted
in a rubber shell (old innertube) or some such
dynamic, so no battery is needed on the bass
also, i put my volume and a tone control on the
bass side when using a dynamic... _ .047 Mfd
capacitor through a 20K ohm pot to ground will
kill all the highs on the bass... you cannot mix
this directly with the output from the powered side,
a second 20K ohm pot for Volume... look for a nice,
long threaded barrel model of potentiometer for
ease of installation
i also use wireless in stereo
now, feedback on the treble depends on the amplified
sound finding it's way back INTO the grille area, then
bouncing back up into the Mic's
in the loudest situations, i actually use the Senn
system, but mounted in a "rail" which i strap
across the grille, which gives a great angle for
pickup with improved rejection of bounce
dampening the inside of the grill isn't a big
help here, but if you can felt some open areas
around the valve plane, between the palletts and such,
so less area is available to reflect sound re-entering
the grille
you can also make small rubber dams around your
elements to help shield from wide angled bounce...
but not too narrow
and while you're at it, use a dab of Silicon Rubber
stuff here and there to lock the wires into place
(greatly reduces the chance of failure due to a
frayed or pinched wire)
if you are even in the DC area (College Park, MD.)
you are welcome to visit the Studio and see the
various Mic systems i'm using
Ciao
Ventura
Len Killick
>
> the closeup of your bass side does not look like the
> Sennheiser element, which is smaller and shaped somewhat
> like an old fashioned Watertower (like the Warner Bros.
> cartoon image, if you've never seen one in real life)
> amd a small hole in the center of the domed top
>
I looked at the bass element too, and wasn't sure: the picture doesn't
show the end of the capsule where the point is in the Sennheiser
version, the cheaper version is just a black flat surface, and the
complete capsule unit is bigger. In the treble side photos I could see
the Sennheiser look, so I assumed the bass was too... but worth
checking.
Ventura
you made me look again, and i finally figured out how to
get the larger image to display
you're probably right - i can't quite tell - good
thing i can learn by ear and memorize quick (lol)
and looking again, i don't care for the placment of the
bass element - i prefer to mount mine down near
the bass strap anchor - more room to feather the nest
and isolate a mic from vibration - with the power and
mix and size of the bass waveforms, the sound rolls
around pretty evenly anyway - while in it's current
position it would be a lot closer to the exit louvre
(which is where the amped sound bleeds back in)
i usually change the angle of the treble element positioning
if the action mechanism allows room to do it...
a pair of long needle nose pliers (one straight one
right angle) work for me, and as i said, i end up with
all 4 senn elements on the treble
ciao
Ventura
ps: you know, i wouldn't be suprised if they still
have a couple new "old stock" Tigers in that warehouse
Viktor
Thank you for the good answers! The best thing about the Internet is
when finding a community with people who share interests, and really
want to exchange ideas! Unfortunately my English is not perfect, and
I do not understand all technical terms, so there will come a couple
of extra questions.
About the TIGER. I found out about the accordion by luck through this
side: http://iralith.livejournal.com/tag/posts+beginning+with+%22so%22
The owner had bought a completely “new” red TIGER in New Hampshire
(they came in red blue and yellow). The shop also had a used, which
cost around 1100$. I was lucky to buy mine through EBAY for 370$. It
STILL could be very interesting for me also to hear, if the warehouse
you were talking about, had any “new” TIGERS! Please let me know if
you hear something ;-)
The acoustic sound from the TIGER is not especially good. But since Im
playing in this very loud playing rockband, it’s MUCH more about
attitude and avoiding feedback than the acoustic sound.
I’m in my summerhouse right now, so it’s not possible for me to have a
closer look. But the man who put in the MT04 system is a well-known
accordion specialist in Denmark, so I don’t think he would put his
name at stake cheating me. Never the less, he told me he is not an
electronic-specialist – which I think you also can see in the
soldering (is it called that?).
I certainly will stick some felt inside the accordion to remove some
of the feed. I do also imagine, covering the inside of the metal-
cover, where the system is put (treble side) would help some, since
the metal-cover might work as sort of giant microphone of the
amplified sounds.
As you write, I also am doubtful about the placement of the bass-mike.
Also because it points away form the sound and towards the chassis.
The mike-system is not put up in stereo, so I cant adjust the tone for
the bass-side easily, as Ventura suggested. It might confuse that on
the picture there is a tone control. It’s the original tone control
knob from the mike inside the bellows, now working as volume control
for the bass-side.
Interesting idea to put a Shure Green Bullet element on the bass-side,
but this also demands a new setup of the system. Right now the battery
(for both sides) is set up on bass-side. Maybe I should find a expert
in electronics here in Denmark to help me out. I should be able to do
some myself though…
Ventura: Could you PLEASE help me out understanding the following?
”Feather the nest”,
”needle nose pliers”,
and what exactly do you mean by: “in the loudest situations, I
actually use the Senn-system, but mounted in a "rail" which i strap
across the grille, which gives a great angle for
pickup with improved
rejection of bounce”?
Thank you VERY much.
Viktor
DoN. Nichols
> Hello again!
>
> Thank you for the good answers! The best thing about the Internet is
> when finding a community with people who share interests, and really
> want to exchange ideas! Unfortunately my English is not perfect, and
> I do not understand all technical terms, so there will come a couple
> of extra questions.
Your conversational English is quite good, however.
> cost around 1100$. I was lucky to buy mine through EBAY for 370$. It
A minor point -- it is common to place the currency symbol to
the left of the amount in US Dollars, so those would be $1100 and $350.
[ ... ]
> name at stake cheating me. Never the less, he told me he is not an
> electronic-specialist ? which I think you also can see in the
> soldering (is it called that?).
Yes, it is.
[ ... ]
> Ventura: Could you PLEASE help me out understanding the following?
I'm not Ventura, but I will jump in on the first two at least.
> ?Feather the nest?,
Commonly used slang term for building up monetary savings
against future need (as a bird builds its nest for future use), but in
this case probably indicating putting sound absorbing material in the
path from the outside of the instrument to where the microphones are
located to minimize feedback.
> ?needle nose pliers?,
A common technical term for pliers used in electronic work and
some other things. They have long thin jaws for reaching into where you
need to bend a lead around a terminal or something of the sort. Let me
see if I can find illustrations of them on eBay auctions. You probably
know them, but by a different name. I would be interested to know what
terms are common where you are.
Straight needle nose pliers are such as found in eBay auction
# 180375319759 -- though I would not agree about these being
collectible.
And this auction: # 260443451713 shows the bent nose needle nose
(along with extra long reach handles).
This one is a nicer condition example of newer straight needle
nose pliers: # 130317363134
And this one is a nicer condition example of the bent nose ones:
# 320394248843 In case it may confuse you, "Snap On" is a tool vendor,
who normally sells to the automotive repair market. Quality tools, but
typically overpriced.
As for the following, other than "Senn-system" meaning "Sennheiser
system", I'll leave it to Ventura to describe what he means in plain
English with a minimum of slang terms. But I think that he means the
microphones are mounted on a bar (wood, metal, or whatever) which is
attached outside the instrument with the microphones pointed towards the
grille and away from the speakers.
> and what exactly do you mean by: ?in the loudest situations, I
> actually use the Senn-system, but mounted in a "rail" which i strap
> across the grille, which gives a great angle for ?pickup with improved
> rejection of bounce??
I hope that this is a help.
Squeeze On,
DoN.
--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
Viktor
Certainly! Thank you for the effort!
Ventura emailed me pictures of rail-systems, so now I am totally
updated!
I think I will start with "felting" the inside, and see how much that
gives.
Yours Viktor.
Len Killick
> and looking again, i don't care for the placment of the
> bass element - i prefer to mount mine down near
> the bass strap anchor - more room to feather the nest
> and isolate a mic from vibration - with the power and
> mix and size of the bass waveforms, the sound rolls
> around pretty evenly anyway - while in it's current
> position it would be a lot closer to the exit louvre
> (which is where the amped sound bleeds back in)
>
> i usually change the angle of the treble element positioning
> if the action mechanism allows room to do it...
> a pair of long needle nose pliers (one straight one
> right angle) work for me, and as i said, i end up with
> all 4 senn elements on the treble
>
I also usually mount the bass near the "bottom" of the instrument and
pointing more or less straight up, never had any problem with that
with both Sennheiser or the standard elements.
The treble positioning of both the complete strip and the angling of
the microphone elements seems to me to be very instrument specific.
When I have an "new" type of accordeon to do I usually experiment a
bit without fixing the strip in permanently before I do the final
fixing!
Len
Ventura
Len Killick wrote:
>
> The treble positioning of both the complete strip and the angling of
> the microphone elements seems to me to be very instrument specific.
it would seem so by looking at it, but my first
powered capsule Mic's and pre-amps were home grown
with RadioShack elements, then with surplus
telex computer capsules and a wide variety since
how many, where, and angle has always been an
interesting amd ongoing experiment
right from the first it made little sense to me
using the electret on Bass, particularly since i
had been running in Stereo for years prior to the
"kit" coming on the market, so actually the first
senn kit (from Master) i installed took the
"put all 4 capsules on the treble" approach
so, if the angle of the capsules on the board was
to smooth out and make the pickup pattern slightly
wider (only 3 points of collection) then clearly
using 4 would allow a more direct (closer to 90 degrees)
angle of alignment with a smooth result
that was my logic, and i'm stickin' with it (lol)
> When I have an "new" type of accordeon to do I usually experiment a
> bit without fixing the strip in permanently before I do the final
> fixing!
>
> Len
and the isolation from vibration, which was the killer
weakness on that one system we reviewed, is also
important... consider that cheap but nice looking
Vocal Mic that seems to amplify the motion of your
finger sliding up the barrel >VS< a good Shure mic
which seems to be able to ignore pretty much
everything except your voice... i've even handled
Mic's that made the cable microphonic to an extent!
the capsule isolation was so poor or non-existent
there is a lightweight open cell foam tape used
in the automotive trim industry which holds like
death itself and which i have been using for quite
some time now... a double layer under these Mic
strips gives excellent damping against vibration
it's available in white or black, costs about 2-3 times
the standard 3M foam mounting tape
ciao
Ventura
Ike Milligan
Yours Viktor.
"Once more, with felting".-- Ike
Viktor
Here are some pictures of my Felting-the-Tiger Project:
http://www.flickr.com/photos/31544092@N06/sets/72157621811385233/
I bought some accoustic-rubber used by car-hifi-enthusiasts, and them
some felt used under chairs and such.
Wednesday I will play with my Islandic punk-rock band, and hope the
feed has gone forever!
I will return!
- Viktor
Viktor
Returning...
The bass-side works totally perfect. No feed! And the sound is still
great I think the chambers I made, isolating the mike from the outside
plates, worked very well.
The right side still has problems. Have to felt and rubber some more.
Thanx for all your suggestions. The most important, I guess, is trying
and trying.
- Viktor
ciao.accordion
live sound
now that you have the Bass side working well,
(and when you output in stereo)
here's another tip... something i used to use
in Georgetown on Rock and Roll gigs...
you can run that bass mic through an FX pedal
just like Fender Bass... a Bass EQ pedal can
really fatten up the tone for instance, and an
octave doubler will work fine when you are
doing just Bass runs... you can use chorus or
flange to a degree depending on how you attack
the notes
but stick with Bass design pedals, as they have the
circuitry to handle the really low end, while many
Guitar pedals don't
FX that need the sustaining decay of a bass string
won't work very well, of course
Ciao
Ventura
Viktor
wrote:
> glad to hear you are getting somewhere with your
> live sound
>
> now that you have the Bass side working well,
> (and when you output in stereo)
> here's another tip...
Sound like an interesting idea! The thing is, the system is not set up
for stereo. I don't know how easy it is to change? Not to crazy about
having two cables coming out from the accordion, but I guess maybe its
not that difficult to set it up with an stereo output (with stereo
cable)?
- V
ciao.accordion
Op Amp and discreet components are primarily
summing the 3 treble mics so one is not louder
than another (making them all equal)
but the Bass mic is just 1 element, and it is
not summed, but mixed, in the mono output model
therefore, it can be broken out into it's own channel
easily (and usually is in most kits, actually) simply
by routing it's output through a 2 to 4 Microfarad
capacitor (you can lift output at the bass volume control)
and then to it's own 1/4" jack (use the common ground,
which also can be tapped at the volume control)
your tech can handle all this easily
making the Ac.bass Killer is very do-able and useful when
there is no bass player on a Rock gig... even though i had
Organ-Accordions as a teen (with electric Bass tones)
still certain bands wanted only acoustic accordion...
so i came up with ways to make the reeds equal the power
of the electronics
in those ancient times (lol) we actually had to
build our own "FX pedals" and the 1 transistor Bass Boost
project was an easy adaptation of the basic 1 transistor
volume boost circuit... then Craig Anderton came out with
an FX project book for Musicians and PAIA made kits to
go with the book (they also made early Synth kits
and had a theremin kit too)
now it's easier... Boss has a pedal for just about everything
ciao
Ventura
Viktor
I'm at the moment not sure whether I will do the stereo thing or not.
I do think Tiger is difficult enough to control as it is...
I did some more felting, and I think I gained a couple of db's, even
though I would have liked to get some more headroom.
At the moment I play over a cheap peavey combo amp. The next thing to
save up for next is a dedicated amp. A danish amp-builder, Lars Reinau
(www.larsreinau.dk ), makes special designed copies of Fenders Tweed
Amp Deluxe. I have visited him once, and he is great at finding tubes
and other components that fits ones individual needs.
Again, thanx for sharing ideas!
- Viktor
Viktor
And one thing that really puzzles me is that I still have this issue
that my treble-side feeds more, when bass-side is turned down. I have
best control over feed from treble-side when bass-side is turned full
and treble-side is turned 3/4 up. This hasn't changed after felting,
even though the bass-side - especially - seems very isolated from
feed. Do you know any logical reason for this?
- Viktor
john
LOL... as I have told you,,, those sennheisers are not good enough,
you can full around with them as much as you want and still will not
get the result you want.......
Viktor
> you can full around with them as much as you want and still will not
> get the result you want.......
Not So Much Laughing: You remind me of those, who make a big deal of
having a Mac rather than PC, Nokia rather than Iphone, Yamaha rather
than Honda... or vice versa. If you have a point, I would like to hear
the clever argument. Otherwise, please...
- Viktor
ciao.accordion
yeah, just ignore him...
look, you are doing it old school...
messing around with your own instrument, taking
ownership of your sound, learning by experimenting,
empirically testing ideas and materials...
in the old days there were many of us who lived
this way... and the end result is your music and
sound will be unique, as is your approach... you
will get more out of your instrument because your
efforts have given you a more intimate connection
to those keys, palettes, reeds, etc. that went into
making it and connect you to your notes in the air
nowadays, people just buy some fancy, tricked out car
with gold plated emblems, take it to competitions, then
strut around as if they actually did something or
deserved recognition... the old definition of "Chopper"
meant you poured YOUR blood, sweat and tears into a ride
with your own mind and hands until it became your own
i hope you keep your interest and willingness to
get under the grille your whole life, and i hope
you stick with Accordions
keep up the good work and remember, you are always
welcome here.
Ciao
Ventura
Viktor
> messing around with your own instrument, taking
> ownership of your sound, learning by experimenting,
> empirically testing ideas and materials...
Hehe, well sometimes I (ant others) DO feel that I use to much messing
around, in stead of just playing. But I convince myself that I play
better when the instrument is exactly like I want it. I guess the
truth lies somewhere in the middle.
Ventura, do you know what happens with the issue explained (treble-
side feeds more, when bass-side is turned down)?
Thanx!
- Viktor
DoN. Nichols
> - Forgot: The tweed amp I want has got 2X12' for deep sound.
Hmm ... I *hope* that you mean 2x12" not 2x12'. The first is
two speakers about 300mm in diameter. The second is two speakers 3.65
*meters* in diameter, and thus would be rather difficult to take to
gigs. :-)
But that would certainly be capable of deep sound. :-)
My own preference for deep sound would be 15" speakers (381 mm)
but that would be for a fixed installation in the home for a good
quality audio system.
> And one thing that really puzzles me is that I still have this issue
> that my treble-side feeds more, when bass-side is turned down. I have
> best control over feed from treble-side when bass-side is turned full
> and treble-side is turned 3/4 up.
Hmm ... this suggests that the treble side is loaded a bit by
the bass side.
> This hasn't changed after felting,
> even though the bass-side - especially - seems very isolated from
> feed. Do you know any logical reason for this?
The electrical loading of the treble side's output by the bass
side seems to make sense to me. What would make this easier to trace
would be to have a stereo output (it could be a three-circuit 1/4"
(6.35mm) phone plug which uses the sleeve as a common ground, tip as the
left channel and ring as the right channel. Then you could individually
control the volumes at the sound system's mixer, fully turning down the
treble (at the mixer) and seeing whether you could create feedback using
just the bass microphones. I suspect that you can't, and that the
feedback (not "feed" BTW) is coming from the treble side.
A graphic EQ (equalizer) can be useful to reduce the sensitivity
at the frequency at which the feedback is occurring, to tune it out.
Ideally, this is done with the aid of a graphic display of frequency
output, so you can see the spike where the feedback is, and turn down
that frequency. Then boost the volume, and tune down the gain at the
frequency of the next spike, and so on until you can get a bit more
volume than you really need, after which you turn the volume down to
reasonable levels and can feel free to not worry about feedback.
A parametric equalizer can be used in a similar way, but is
perhaps a little less intuitive with a graphic display of the feedback
frequencies.
Out of curiosity -- is your current amplifier and speaker an
open backed arrangement? And is it standing in front of you on the
stage? If so, you might be able to reduce the feedback significantly
just by moving it to stand beside you instead of in front of you --
ideally on the bass side so it has less access to the treble-end
microphones.
Good Luck,
Viktor
> What would make this easier to trace
> would be to have a stereo output (it could be a three-circuit 1/4"
> (6.35mm) phone plug which uses the sleeve as a common ground, tip as the
> left channel and ring as the right channel. Then you could individually
> control the volumes at the sound system's mixer, fully turning down the
> treble (at the mixer) and seeing whether you could create feedback using
> just the bass microphones. I suspect that you can't, and that the
> feedback (not "feed" BTW) is coming from the treble side.
Don, I don't understand the difference between your suggestion, and
what I can do right now. Probably I have not explained exactly what
happens. Maybe you did understand me, and I don't get it! :-)
Just to clarify: I have two volume knobs on the accordion, one for
bass-side and one for treble-side, sending the sound out together in
mono.
When I turn down bass (0) and turn up treble (full) I have some
feedback, when I turn up bass (full) and turn down treble (0) I have
no feedback.
When I turn up both (3/4) I have some feedback.
But the thing is when I turn bass up full and keep treble on 3/4 I get
less feedback(!) than both on 3/4.
It seems to me to be a phase-problem of some sort. Logically I don't
get it, since the bass-side (after felting) is very well acoustically
isolated and gives very little feedback, suggesting that the bass-side
microphone should not phase interfere with the treble-side.
Therefore I was wondering if maybe it was a wiring-problem of some
sort.
Maybe that is also what you suggest when you write:
>The electrical loading of the treble side's output by the bass
side seems to make sense to me.
I don't understand how the treble sides output can be electronically
loaded by the bass-side. If this is the problem, what I can do?
> Out of curiosity -- is your current amplifier and speaker an
> open backed arrangement? And is it standing in front of you on the
> stage?
Actually I am trying different options out right now. I must say that
the feedback problem is not so big anymore. I WOULD have liked some
more headroom, but I think that is impossible when you think of how
loud my band is playing (crazy). Its actually not so much a live
problem, but more when in rehearsal-studio. In a live situation I have
the amp behind me as a guitar player would have. When I turn my body
towards the amp, I turn counter-clock-wise to avoid the treble-side
being exposed in front of the speaker.
Thank you.
- Viktor
David Kastrup
>>�What would make this easier to trace
>> would be to have a stereo output (it could be a three-circuit 1/4"
>> (6.35mm) phone plug which uses the sleeve as a common ground, tip as the
>> left channel and ring as the right channel. �Then you could individually
>> control the volumes at the sound system's mixer, fully turning down the
>> treble (at the mixer) and seeing whether you could create feedback using
>> just the bass microphones. �I suspect that you can't, and that the
>> feedback (not "feed" BTW) is coming from the treble side.
>
> Don, I don't understand the difference between your suggestion, and
> what I can do right now. Probably I have not explained exactly what
> happens. Maybe you did understand me, and I don't get it! :-)
>
> Just to clarify: I have two volume knobs on the accordion, one for
> bass-side and one for treble-side, sending the sound out together in
> mono.
>
> When I turn down bass (0) and turn up treble (full) I have some
> feedback, when I turn up bass (full) and turn down treble (0) I have
> no feedback.
> When I turn up both (3/4) I have some feedback.
> But the thing is when I turn bass up full and keep treble on 3/4 I get
> less feedback(!) than both on 3/4.
So what? You'll have some passive circuitry inside for volume control
and mixing. So a combination of bass volume control and bass mic will
act as a load on the output of the treble mic/control. Just how much
and in what respect depends on the exact circuitry employed.
> It seems to me to be a phase-problem of some sort. Logically I don't
> get it, since the bass-side (after felting) is very well acoustically
> isolated and gives very little feedback, suggesting that the bass-side
> microphone should not phase interfere with the treble-side. Therefore
> I was wondering if maybe it was a wiring-problem of some sort.
As long as you have no battery (and active circuitry) inside, the mics
and volumes will not work independently (there is likely a theoretical
trick using double pots and bridge wiring possible, but I doubt is is
ever employed).
>> The electrical loading of the treble side's output by the bass side
>> seems to make sense to me.
>
> I don't understand how the treble sides output can be electronically
> loaded by the bass-side.
How could it not? Could you present a circuitry where this would not be
the case?
--
David Kastrup
Viktor
> > I don't understand how the treble sides output can be electronically
> > loaded by the bass-side.
>
> How could it not? Could you present a circuitry where this would not be
> the case?
Oh, I misunderstood. My bad.
I am most happy as it is now! Just wanted everything to work 100%
Thanx a lot!
- Viktor
ciao.accordion
i pulled the old kit box off the shelf, as on it
i had drawn out a de-construction of the circuit
(before i installed it) this one went into
the Excelsior 960
the only difference: each of the 3 treble Mic's
is weighted with an extra 10K ohm resistor on their
way to their 15K ohm Pot wiper leg (Volume Treble)
the Bass mic is not weighted and connects directly
to it's 15K pot wiper leg (Volume Bass)
both pot's tie to the same leg of the op amp and to ground
respectively at opposite legs of the 15K ohm carbon traces
so, i guess when both pot wipers are at ground,
the treble mics would "see" about 40K ohms in a path
through the Bass pot relative to 25K ohms to ground
through it's own pot. When the treble wiper is full up,
the mic's would each see 10K ohms to the op amp input,
relative to 25K ohms through the bass pot to ground
the ratio's do change a bit... but
there do not seem to be any capacitors other than the couplers,
so i can see no reverse leakage path for (some) frequencies
(as an unintentional tone circuit might bleed) in reverse through
the wiper of the Bass potentiometer
can the electret elements themselves have a capacitance that can
allow a reverse bleed of sorts? i thought they were more like
transistors with one leg attached to the foil, but perhaps
they have a tiny LC circuit of discreet components built in
to the capsule?
Ciao
Ventura
DoN. Nichols
> Hi!
>
>>�What would make this easier to trace
>> would be to have a stereo output (it could be a three-circuit 1/4"
>> (6.35mm) phone plug which uses the sleeve as a common ground, tip as the
>> left channel and ring as the right channel. �Then you could individually
>> control the volumes at the sound system's mixer, fully turning down the
>> treble (at the mixer) and seeing whether you could create feedback using
>> just the bass microphones. �I suspect that you can't, and that the
>> feedback (not "feed" BTW) is coming from the treble side.
>
> Don, I don't understand the difference between your suggestion, and
> what I can do right now. Probably I have not explained exactly what
> happens. Maybe you did understand me, and I don't get it! :-)
>
> Just to clarify: I have two volume knobs on the accordion, one for
> bass-side and one for treble-side, sending the sound out together in
> mono.
Yes -- I assumed that. This probably means that you have
something like the following (view this with a fixed pitch font like
Courier -- proportional pitch fonts will cause things to squish to the
left by differing amounts and things will no longer line up properly,
leading to confusion.
|)-|>--+
Z TREB
Z<------o--+-----o-----v || Mono jack
Z | o---------
Z | |
| | ---
___ | -
- |
|
|)-|>--+ |
Z |
Z<------o--+
Z BASS
Z
|
___
-
Now -- the "|>" symbols are microphone preamps, and the "|)"
symbols are microphones. The 'Z' columns are a resistance element of a
volume control.
Assume that the bass volume control is turned all the way up,
and the output impedance of the preamps are rather low compared with the
resistance of the volume controls. This means that the output point
sees the very low output impedance of the preamp, because the wiper of
the potentiometer is all the way up, resulting in very little resistance
between the preamp output and the output line from the volume control.
This means that the treble (which is not all the way up) has to
go through the resistance of the upper section of its volume control and
can't drive the outout of the bass preamp very well. (This is the
"loading".
If, instead, there is a resistance from the output of each of the
volume controls to the point where the two are joined to go to the jack,
then you don't have this loading effect.
However -- what I was suggesting is what is below -- using a
stereo phone cable (Tip-Ring-Sleeve) instead of a two conductor mono
one, which is only tip and sleeve). This allows each side to go into a
different input preamp in the mixer, and the design of any good mixer
will prevent any such loading effect. This way, you can see what is
sensed by each microphone set, and control whether it gets to the
speaker without affecting the other.
|)-|>--+
Z TREB
Z<------o--+-----o-----v || Stereo jack
Z +-----o------^||
Z | o-------||
| | |
___ | ---
- | -
|
|)-|>--+ |
Z |
Z<------o--+
Z BASS
Z
|
___
-
> When I turn down bass (0) and turn up treble (full) I have some
> feedback, when I turn up bass (full) and turn down treble (0) I have
> no feedback.
Which says that the feedback is coming through the treble side
only.
> When I turn up both (3/4) I have some feedback.
> But the thing is when I turn bass up full and keep treble on 3/4 I get
> less feedback(!) than both on 3/4.
Yes -- because the loading from the bass preamp through a fully
up volume control is reducing the amount of the treble which actually
gets out to the amplifier.
> It seems to me to be a phase-problem of some sort.
I don't think so, because the phase will vary with how far the
bellows is extended, and you don't mention that as one of the things
which affect your feedback.
> Logically I don't
> get it, since the bass-side (after felting) is very well acoustically
> isolated and gives very little feedback, suggesting that the bass-side
> microphone should not phase interfere with the treble-side.
It should not -- but the bass side preamp can load down the
output of the treble side with the volume controls set as you have
described.
> Therefore I was wondering if maybe it was a wiring-problem of some
> sort.
Only in that there is no isolation following the volume
controls. Ideally, there would be a tiny mixer there with the two
volume controls feeding through different resistors into a summing
amplifier.
> Maybe that is also what you suggest when you write:
>
>>The electrical loading of the treble side's output by the bass
> side seems to make sense to me.
>
> I don't understand how the treble sides output can be electronically
> loaded by the bass-side. If this is the problem, what I can do?
It is quite likely, if the wiring is as I drew it in the first
drawing above, and I hope that my explanation made it make more sense.
You can eliminate it by either re-wiring as a stereo output as I
drew in the second drawing, assuming that your mixer can treat the sides
of a stereo jack as separate (look for a balance pot on the channel of
the mixer into which you are plugging it. Some may not have stereo
inputs at all.
Or -- you can put an active mixer circuit between the volume
controls and the output jack. You can probably find a lot of drawings
showing such using operational amplifiers. The schematic gets a bit
more complicated and I don't want to try drawing it using ASCII graphics
as I did above.
>> �Out of curiosity -- is your current amplifier and speaker an
>> open backed arrangement? �And is it standing in front of you on the
>> stage?
>
> Actually I am trying different options out right now. I must say that
> the feedback problem is not so big anymore. I WOULD have liked some
> more headroom, but I think that is impossible when you think of how
> loud my band is playing (crazy).
I hope that you are wearing hearing protection while you play
there.
> Its actually not so much a live
> problem, but more when in rehearsal-studio. In a live situation I have
> the amp behind me as a guitar player would have. When I turn my body
> towards the amp, I turn counter-clock-wise to avoid the treble-side
> being exposed in front of the speaker.
That helps -- though it would make more sense to have the
speakers in front of you, with closed backs, so they minimize the
exposure of the instrument's microphones to the speaker's sound.
However, you probably need the current placement of the speakers to hear
what the others in the band are playing -- if you don't have separate
stage monitors and house mix -- with someone running a mix board to do
this properly.
Best of luck,
DoN. Nichols
> hi DoN,
>
> i pulled the old kit box off the shelf, as on it
> i had drawn out a de-construction of the circuit
> (before i installed it) this one went into
> the Excelsior 960
O.K.
> the only difference: each of the 3 treble Mic's
> is weighted with an extra 10K ohm resistor on their
> way to their 15K ohm Pot wiper leg (Volume Treble)
>
> the Bass mic is not weighted and connects directly
> to it's 15K pot wiper leg (Volume Bass)
>
> both pot's tie to the same leg of the op amp and to ground
> respectively at opposite legs of the 15K ohm carbon traces
Hmm ... the wipers of both go directly to the same input pin on
the op amp? But there is an op amp after the pots. Yes, that is asking
for one to load the other somewhat.
> so, i guess when both pot wipers are at ground,
> the treble mics would "see" about 40K ohms in a path
> through the Bass pot relative to 25K ohms to ground
> through it's own pot.
Since the bottom end of both pots is ground, you can ignore
paths through the bottom ends of the two pots. The path to ground
over-rides everything else. (You can perhaps refer to my ASCII
schematic which I just posted in another branch of this thread -- and
perhaps cut and paste it and add the op-amp circuit to the drawing?
> When the treble wiper is full up,
> the mic's would each see 10K ohms to the op amp input,
> relative to 25K ohms through the bass pot to ground
The same 10K resistor for both, or separate ones for each? If
the same one for both, then then yes, a lot of cross loading. If you
have separate resistors to the op amp pin for each, and a third
(typically much higher value) resistor coming back from the output, then
you should have a pretty clean summing junction and not have any cross
effects between the two pots.
But what is the output impedance of the electrets (now that I
know that they are electrets)? That might be difficult to determine,
but if it is a direct transistor output, then the output impedance is
likely pretty low compared to the pot impedances.
> the ratio's do change a bit... but
>
> there do not seem to be any capacitors other than the couplers,
> so i can see no reverse leakage path for (some) frequencies
> (as an unintentional tone circuit might bleed) in reverse through
> the wiper of the Bass potentiometer
>
> can the electret elements themselves have a capacitance that can
> allow a reverse bleed of sorts? i thought they were more like
> transistors with one leg attached to the foil, but perhaps
> they have a tiny LC circuit of discreet components built in
> to the capsule?
Well ... an electret is essentially a small variable capacitor
(varied by the position of the diaphragm) with a permanent charge
(usually formed by applying voltage while the electret's dialetric sets)
which can then be applied to the gate of a FET (very high impedance
there) and this is converted by the FET (field effect transistor) to a
much lower impedance to survive passing through a moderately long cable
to the mixer. The low impedance output from those results in
significant loading of other branches of the circuit, depending on the
setting of the pots. And if there is no resistor in series with the
bass mic, then it *will* load the output of the others at top pot
settings.
Squeeze On,
David Kastrup
> On 2009-08-13, ciao.accordion <ciao.ac...@verizon.net> wrote:
>> hi DoN,
>>
>> i pulled the old kit box off the shelf, as on it
>> i had drawn out a de-construction of the circuit
>> (before i installed it) this one went into
>> the Excelsior 960
>
> O.K.
>
>> the only difference: each of the 3 treble Mic's
>> is weighted with an extra 10K ohm resistor on their
>> way to their 15K ohm Pot wiper leg (Volume Treble)
>>
>> the Bass mic is not weighted and connects directly
>> to it's 15K pot wiper leg (Volume Bass)
>>
>> both pot's tie to the same leg of the op amp and to ground
>> respectively at opposite legs of the 15K ohm carbon traces
>
> Hmm ... the wipers of both go directly to the same input pin on
> the op amp? But there is an op amp after the pots. Yes, that is asking
> for one to load the other somewhat.
I think that not the wipers, but rather the off-ground end of the pots
go to the opamp. That way, if a pot is at zero, the _mic_ gets shorted
rather than the opamp (and the latter would most certainly shut down the
treble as well).
--
David Kastrup
David Kastrup
I think the circuit is rather:
TREB
+-------o--+-----o-----v || Mono jack
Z | o---------
|)-|>->Z | |
Z | ---
Z | -
| |
___ |
- |
|
+-------o--+
Z BASS
|)-|>->Z
Z
Z
|
___
-
Now if you turn the bass down, the load is just the pot. If you turn
the bass up, the load on the treble is the pot in parallel with the
mic. Assuming that the mic is similar to the treble mic in its
electrical characteristics, the bass mic will about halve the treble
mics output voltage if connected in parallel without any other load.
Since there already _is_ other load (namely the pots), the effect will
be less pronounced.
--
David Kastrup
ciao.accordion
> ___
> |
> Z
> Z<------o---|(--- 1 Uf --- from bass mic
> Z BASS
> Z
> |
> |)-|>--+>-----output bass
> |
> |
> |>------combined output to op amp---)|--- 1 Uf ---
> |
> |
> |)-|>--+>-----output treble
> Z
> Z TREB
> Z<------o--+-----o~~10K~~o------<--|(-- 1 Uf -- Mic Element #1
> Z +-----o~~10K~~o------<--|(-- 1 Uf -- Mic Element #2
> Z +-----o~~10K~~o------<--|(-- 1 Uf -- Mic Element #3
> |
> ___
> -
>
forgive me
ciao.accordion
> ___
> |
> Z
> Z<------o---|(--- 1 Uf --- from bass mic
> Z BASS
> Z
> |
> |)-|>--+>-----output bass
> |
> |
> |>------combined output to op amp---)|--- 1 Uf ---
> |
> |
> |)-|>--+>-----output treble
> Z
> Z TREB
> Z +----o~~10K~~o---<--|(-- 1 Uf -- Mic Element #2
> Z +----o~~10K~~o---<--|(-- 1 Uf -- Mic Element #3
> |
> ___
> -
>
forgive me
DoN. Nichols
> "DoN. Nichols" <dnic...@d-and-d.com> writes:
[ ... ]
This is a *very* atypical use of potentiometers, and has the
disadvantage of putting a short circuit load on the mic preamps (which
may actually built into the mic itself).
The way I drew it -- the normal use of potentiometers -- you get
an adjustable voltage divider to pass on a percentage of the voltage
from the microphone preamps. However, I do see that with the normal
setup, if you turn one fully down and the other some degree of up, you
will short the output of the one which is partially or fully up. This
might be a reason for the otherwise unusual design which you are showing
-- which eliminates the need for isolation resistors after the
potentiometer wipers to prevent such loading. This assumes that the mic
preamps are not going to be harmed by the low impedance load of a pot
turned all the way down. (And -- I would expect it to draw bit more
power under those conditions as well.)
> Now if you turn the bass down, the load is just the pot. If you turn
> the bass up, the load on the treble is the pot in parallel with the
> mic. Assuming that the mic is similar to the treble mic in its
> electrical characteristics, the bass mic will about halve the treble
> mics output voltage if connected in parallel without any other load.
I got the impression from another post in this thread that there
was a "tuning" resistor in series with each of the treble microphones,
to balance the output from the three, so this would make it easier for
the bass mic (without such a resistor) to significantly load the output.
The real test as to which wiring scheme is in use would be
whether you get the same loss of treble sensitivity if you turn the bass
all the way down instead of up. If so, it is likely to be something
like my suggested circuit. If not, then it is likely to be like yours.
> Since there already _is_ other load (namely the pots), the effect will
> be less pronounced.
Understood.
Squeeze On,
Viktor
Impressive(!)
DoN:
> However -- what I was suggesting is what is below -- using a
> stereo phone cable (Tip-Ring-Sleeve) instead of a two conductor mono
> one, which is only tip and sleeve). This allows each side to go into a
> different input preamp in the mixer, and the design of any good mixer
> will prevent any such loading effect. This way, you can see what is
> sensed by each microphone set, and control whether it gets to the
> speaker without affecting the other.
I have learned a lot here, but Im very new at electronics, so I hope
you have patience with me!
I am about to buy a Fender tweed mono tube amp, with 2x12", that will
be tweeked for the accordion. My idea is to play the bass-through a
"clean" input, and treble side through a more distorted channel. My
amp-builder says this is possible, and a good idea (we haven't tried
it yet - wednesday). As I understand it, the two inputs do not go
though different preamps, but the preamp tube just handles the
different inputs differently, and (sort of) works like two tubes.
To do this I have to change my output on the accordion from mono to
stereo, but I (slowly me) still don't understand why there is a
difference between having one stereo output which splits out to two
inputs on the amp, and having two mono outputs doing the same. Is
stereo output the best solution for this? (I would have chosen this
out of practical reasons, one wire instead of two).
> I hope that you are wearing hearing protection while you play
> there.
I certainly am!!!
THANX!
- Viktor
ciao.accordion
a stereo cable, tip ring sleeve, is just fine in
general, but personally I prefer 2 mono outputs
on the accordion
1> this allows for more robust and varied cabling,
as it is easier to get rugged right angle 1/4" mono
plugs, and easier for me to solder them up (I make
all my personal audio cabling)
2> going wireless is next to impossible if you have
to break out the damn 3 way jack first with some
kinda wire hangin' off your hip
which leads me to that... i mean, if you are getting
really into this and at the point of spending serious
bucks on your system, why not cut the cord? I've been
totally wireless for 2 decades now, and am MIDI wireless
as well for over 2 years... you are in Europe somewhere?
well you must have access to those awesome Sennheiser
wireless systems...
but then i'd also have to say, IMHO, the Tube gear
you are considering is completely unnecessary... there
is absolutely no interactive relationship between a 12ax7
and an electret Microphone that would be of benefit.
We are discussing Audio here, not humbuckers, and
using your Pre-amp and Amp as a huge tone control
is like going back to the dark ages
next, an amp with twin 12's is not a bad choice for Accordion,
except the models of value to you would be like a Roland
JC-120, a Peavey Twin Chorus, or a Crate Stereo Chorus...
the Fender is designed for Punch, not Heart...
i have nothing against a dedicated amp unit
for Accordion... still have my Ampeg Olympian
(originally loaded with twin 15" Altec's) which
i used extensively through the 70's on gigs
where i was just a sideman and didn't need a full PA
distortion does not work on Microphones and reeds...
you don't have the sustaining waves of a guitar string
and your attack is abrupt, with the "A" of your
ADSR more often going to drive the Distortion into
unpleasant cracking... nor can you clip reeds
without losing the dynamics that make them awesome...
reeds just end up sounding like a Ruptured Duck
before you waste beaucoup bucks (Euro's) you might
want to explore more options and experiment a bit
with a friends gear
I have nothing against Tubes... gigged for decades
with Green Face Altec Mixers and Amps that could hold
you down in a Hurricane... Quad output (6448's?) in parallel
push-pull configuration (these Amps would still get through
a gig with half the circuit down) but even then i selected
this equipment because it did NOT do anything to my sound
except MAKE IT LOUDER with great reliabilty... for
Rock and Roll driving Voice of the Theater cabinets
and some old Long Dual Horns we'd lay across the tops...
i still have 1 pair of these left... they still work...
but i only fire them up here in the Studio for fun
and nostalgia once in a blue moon... I still have
real Hammonds and a Leslie, but i'm not gonna drag them
to gigs either... my "Drawbar modules" sound great
finally, the other reason to run in Stereo is because
your Bass should never have ANY reverb applied to it,
but often you will want some reverb on the treble, and
in MONO you can't accomplish this
might see if you can borrow a Yamaha Stagepas and compare
that against the fender...
Ciao
Ventura
DoN. Nichols
>
> Impressive(!)
>
> DoN:
>
>> However -- what I was suggesting is what is below -- using a
>> stereo phone cable (Tip-Ring-Sleeve) instead of a two conductor mono
>> one, which is only tip and sleeve). �This allows each side to go into a
>> different input preamp in the mixer, and the design of any good mixer
>> will prevent any such loading effect. �This way, you can see what is
>> sensed by each microphone set, and control whether it gets to the
>> speaker without affecting the other.
>
> I have learned a lot here, but Im very new at electronics, so I hope
> you have patience with me!
>
> I am about to buy a Fender tweed mono tube amp, with 2x12", that will
> be tweeked for the accordion. My idea is to play the bass-through a
> "clean" input, and treble side through a more distorted channel. My
> amp-builder says this is possible, and a good idea (we haven't tried
> it yet - wednesday). As I understand it, the two inputs do not go
> though different preamps, but the preamp tube just handles the
> different inputs differently, and (sort of) works like two tubes.
O.K. It has been a *long* time since I looked at tube circuits,
and I never *designed* anything using them. Solid state devices are
different, and easier to squeeze a lot of functionality into a small
space and low power requirements.
> To do this I have to change my output on the accordion from mono to
> stereo, but I (slowly me) still don't understand why there is a
> difference between having one stereo output which splits out to two
> inputs on the amp, and having two mono outputs doing the same. Is
> stereo output the best solution for this? (I would have chosen this
> out of practical reasons, one wire instead of two).
The primary benefit of the stereo cable is that you need only
one to get the signals to the amp. With mono outputs, you would need
two cables. (Actually -- you will still be using two mono outputs, but
feeding them through a single cable which is normally used to carry
stereo.) It is less of a source of tangles, and less of a chance of
mis-connecting things (feeding the bass through the treble input and
vice versa when setting up on stage) since you have only one cable and
one connector at each end. That same cable can also be used to carry a
mono signal at line level into a balanced input to be more immune to hum
pickup -- but that requires a bit more circuitry in the accordion as
well.
I presume that the microphones are powered from some batteries
in the accordion. There are other tricky ways to power them through the
three conductor cable over the same wires which carry the sound, but
that forces you back to mono. This is commonly used for powering
separate microphones from a mixer -- and is called "phantom power".
But -- you have the choice of feeding the two signals separately
through a single cable, or feeding line level and getting phantom power
to the instrument from a mixer. (I don't think that phantom power will
be easy to set up with a tube amplifier, however, so go for the stereo
feed to the amp through the single cable.
Enjoy,
David Kastrup
> hi Viktor,
>
> a stereo cable, tip ring sleeve, is just fine in
> general, but personally I prefer 2 mono outputs
> on the accordion
>
> 1> this allows for more robust and varied cabling,
> as it is easier to get rugged right angle 1/4" mono
> plugs, and easier for me to solder them up (I make
> all my personal audio cabling)
With that kind of rig, be sure _not_ to make a connection between the
two ground sides for both mics and their plugs on the accordion. If you
do, the separate ground connections on the amplifier, and in the
accordion, and the two separate cables form a "ground loop". Which
catches hums.
> which leads me to that... i mean, if you are getting
> really into this and at the point of spending serious
> bucks on your system, why not cut the cord? I've been
> totally wireless for 2 decades now, and am MIDI wireless
> as well for over 2 years... you are in Europe somewhere?
> well you must have access to those awesome Sennheiser
> wireless systems...
Because the radio frequencies currently used for wireless mics have been
reassigned, and all current wireless mics will be outlawed here in few
years.
--
David Kastrup
ciao.accordion
> Because the radio frequencies currently used for wireless mics have been
> reassigned, and all current wireless mics will be outlawed here in few
> years.
>
Sennheiser has a current, country by country/region
legal frequency on their website
many of the major brands have models that conform
to the new frequency bands
Sennheiser, notably, was one of the first to update
their line
using the chart, it is possible to select units that
have overlapping bands for the various countries
you might visit in future
also, the X2 line6 Digital Audio transmitters
and receivers are using approved frequencies
(at least) here in the USA... i have upgraded
with a pair of the X2 and another pair of XDSplus
and been using them for about a year now
they are excellent... easily the quietest i've ever
found, and range is excellent
Ciao
Ventura
ciao.accordion
>
> With that kind of rig, be sure _not_ to make a connection between the
> two ground sides for both mics and their plugs on the accordion. If you
> do, the separate ground connections on the amplifier, and in the
> accordion, and the two separate cables form a "ground loop". Which
> catches hums.
the Mic's share ground on the circuit-board, whether output
is in Mono or Stereo
the grilles on all my internal mic'd accordions are aluminum,
so the bodies of the jacks are always commonly grounded
all my mixers have always had common ground circuitry, including
my newest Digital Mixer from Roland... without true ground,
the shields in the cables would have nothing to drain to...
if you've ever inadvertantly wired something this way,
you'd find the cable becomes a big capacitor and often
then exhibits a microphonic effect (running your finger
along the cable produces sound, every time the cable is moved
even slightly, you can hear it creak in the speakers... it's
really weird and the first time you experience it,
maddeningly difficult to figure out the cause)
ciao
Ventura
DoN. Nichols
> David Kastrup wrote:
>>
>> With that kind of rig, be sure _not_ to make a connection between the
>> two ground sides for both mics and their plugs on the accordion. If you
>> do, the separate ground connections on the amplifier, and in the
>> accordion, and the two separate cables form a "ground loop". Which
>> catches hums.
>
> the Mic's share ground on the circuit-board, whether output
> is in Mono or Stereo
>
> the grilles on all my internal mic'd accordions are aluminum,
> so the bodies of the jacks are always commonly grounded
This is assuming that the jacks are mounted on the metal grille
instead of on the wood of the box.
and -- there are insulating shoulder washers which can float the
jacks from the metal to which they are mounted.
But if you interrupt the ground on one of the two cables, make
sure that the one with ground is the first to be connected, or you could
have massive hum until the second cable is connected. And actually --
you should have the gain on the amp all the way down until everything is
connected anyway.
> all my mixers have always had common ground circuitry, including
> my newest Digital Mixer from Roland... without true ground,
> the shields in the cables would have nothing to drain to...
You do need at least one grounded -- and that should suffice
when both are connected. But if you do have two separate cables, and
they are routed differently around the stage, you could pick up some
significant ground loops with both ground circuits complete.
> if you've ever inadvertantly wired something this way,
> you'd find the cable becomes a big capacitor and often
> then exhibits a microphonic effect (running your finger
> along the cable produces sound, every time the cable is moved
> even slightly, you can hear it creak in the speakers... it's
> really weird and the first time you experience it,
> maddeningly difficult to figure out the cause)
A linear capacitor microphone. :-)
Squeeze On,
ciao.accordion
>
> and -- there are insulating shoulder washers which can float the
> jacks from the metal to which they are mounted.
i still have a small stash of the Switchcraft squared plastic
bodied 2 and 3 way jacks with the plastic threaded sheath
over the barrel so as to be insulated from the metal panel
these were required on Cordovox repairs, as both -20 and +20
rails were used willy nilly and ground could be found floating
in relative ways and various places about these electronic
nightmares of circuitry
ciao
Ventura
Viktor
Ok, I did put the Fender on hold for a while and tried out many
amplifiers during the last couple of days. Even though I know that the
general attitude among accordion players surely is that solid state
(clean sound) and stereo is the way to go - I am still not convinced
(for my purpose).
I DO like the sort of farfisa/rhodes distorted sound I can get out of
tube amp. But I did try out several other solutions, which made a good
comparison for me. Bass-amps, keyboard-amps, acoustic guitar amps and
PA's (including Yamaha Stagepass). In this area I liked the best
Ashdown basscombo with 4x10" (tried other more expensive bass-amps but
this one worked best for me for some reason - Its quite heavy
though).
I also kind of liked the Peavey KB5 keyboard Amp, especially for the
multiple channels and its portability. I would have really liked to
try out a Trainor K4 Keyboard stereocombo with tubes, but is not
available in Denmark.
The Stagepass and other PA-systems does not do it for me. Maybe I DO
live in the dark ages (I also smoke cigarettes, listen to vinyl
records and own a retro motorbike), but in the style and loudness Im
playing I do like it when the instrument, amp and loudspeaker is
working together as a whole.
Ventura, for me it IS a matter of taste. And there IS interaction,
maybe not directly back from the amp to the capsules, but from the amp
to my ears, my crazy head, fingers and so-forth.
I have found it very difficult to find the right amp, and am still not
totally convinced. Even though my best now, is still a Fender tweed
copy - now with 1X12 Celestion Gold, and some handpicked tubes that an
amp-builder (Lars Reinau) has helped me to find (low gain input and
less midtone than normal). With this I will not get the big bass
sound, but I certainly have got a much better handling of the upper
mid (with a pleasant ligth and warm distortion), than a Yamaha PA can
deliver. The sound I get is very present and organic to me compared
with PA-handling. Maybe still a little to much in the low middle, but
I think an eq-pedal will fix that. The amp will be miked and the PA
can deliver the rest (especially more bass). This combo is very
portable and I have full control over the sound, that I want to hear,
to play my best. Lars Reinau is quite famous among "fine-
schmeckers" (dont know the english word for that). And I guess you
have to know what you are doing when experimenting this way - of
course this task was a first-timer for him. Have tried several other
guitar amps, and most sound absolutely horrible with the accordion.
No, this combo will not work for traditional acoustic gigs. Its for
the kind of rockmusic I play - and its also a matter of attitude.
Still looking, though. I understand the point about stereo handling
the sound. But on the other hand...
About the feedback. Its gone. Rubber and felt everywhere and under the
mikes did it.
Thank you all a lot for showing interest and helping!!!
- Viktor
David Kastrup
> About the amplification....
>
> Ok, I did put the Fender on hold for a while and tried out many
> amplifiers during the last couple of days. Even though I know that the
> general attitude among accordion players surely is that solid state
> (clean sound) and stereo is the way to go - I am still not convinced
> (for my purpose).
Ok, here is some of the beef: distortion (nonlinear amplification) adds
additional harmonics to a periodic signal. Good accordion reeds have
quite a few harmonics of their own, so the motivation is less.
But here is the downside: when we are playing more than one note at
once, the resulting signal has a much larger period (lower frequency).
Distortion will happily add additional "harmonics" on top of this much
lower frequency. The result is more or less noise.
That is the reason that electric guitar distortion is usually limited to
either monophonic melody lines or "power chords" consisting only of a
note and its fifth (the resulting periodicity is then more or less based
on the octave below the lower note).
Now an accordion usually is not employed monophonic: that would render
most of the left side unusable. So distortion will be rather limited in
its applicability. Probably somewhat useful for a diatonic accordion
played without bass notes.
--
David Kastrup
ciao.accordion
> Ventura, for me it IS a matter of taste. And there IS interaction,
> maybe not directly back from the amp to the capsules, but from the amp
> to my ears, my crazy head, fingers and so-forth.
i am certainly satisfied you are considering all aspects,
which is really all that matters
you have some very good support people from the looks
of it, and you may need them because it is critical to
understand if your Amp is your tone shaper, then in a
disaster, you have extremely limited options to fall back to
for the bottom end, i'd like to mention that the bass
frequencies are not very directional, so it may
be a nice improvment if your Amp can handle not only it's
internal speaker (which is pointed at you) but also
drive an auxiliary bass bin (simple smaller wood cabinet
with a Neodymium magnet 15"... i'd suggest the Eminence
Kappalite3015Lf which is a Bass speaker, 40 to 1500 Hertz
with almost 100% sensitivity rating... this can sit in the
darkness behind your Amp and may not be too much of a hassle
to use... plus you can sit on it (lol) stash your Smokes
there, etc.
the Stagepas suggestion was assuming you send your feed
to the main PA, and only need the stage amp so you
can hear yourself, but apparently 100% of your powered
sound will come from your personal Amp system?
ciao
Ventura
Viktor
>most of the left side unusable. So distortion will be rather limited in
>its applicability. Probably somewhat useful for a diatonic accordion
>played without bass notes.
In the band I do often play soloparts and two/three tone harmonics,
but I also use bass side chords in between, and sometimes both
(traditional way). That is also why I do not find guitar amps useful
in general. But this modified tweed amp has much less gain factor,
meaning that the distortion comes in later and much more gentle, and
can be used for full harmonics as well. Of course Im not talking heavy
rock distortion, but more the sound of the fifties/early sixties.
> i am certainly satisfied you are considering all aspects,
> which is really all that matters
Thats me alright. Considering and considering. Sometimes I end up
getting what I want. Sometimes I never get satisfied (sigh)
> i'd suggest the Eminence
> Kappalite3015Lf which is a Bass speaker, 40 to 1500 Hertz
> with almost 100% sensitivity rating.
I have considered investing in a bass speaker - maybe active (a not to
deep subwoofer) - later on. Ill sure check the Eminence!
>plus you can sit on it (lol)
I NEVER sit playing! (I don't headband either... maybe dance a little,
if Im in the mood)
>stash your Smokes there
Now that's a good point! :-)
> but apparently 100% of your powered
> sound will come from your personal Amp system?
I have not ordered the amp yet (its quite expensive). I probably will
soon though. In rehearsal studio my plan is to play primarily on the
amp, probably miked to the PA, which also could give more bass. In
live situation the amp will be miked. Until know I have been playing
directly to the PA in live situations.
:-)
- Viktor
Viktor
I found a Traynor K4 amp in a small town in Denmark. And it is exactly
what I wanted. Stereo, I can change between tube and solid state. So
with a pedal I can change between a distorted sound and a clean. And
when I change my output form the accordion to a separate treble side /
bass side, I can send them respectively to a tube input and a solid
state input. The tubes are chinese, so I will change them later. So
now I am where I wanted to be: very happy!!!
ciao.accordion
> Update:
> I found a Traynor K4 amp
i checked out the specs, and that IS one
powerful and versatile AND wide frequency Amp
post EQ output to the mains when you need it
(so your PA sound is the same as your Amp sound)
unfiltered summed Subwoofer output too!
so you can add (just) more bottom when you need it
only thing is it looks kinda heavy which
(for me) i've spent the last 10 years figuring
out how to make things lighter (lol) but
hey... you are young
though there are excellent high power Neodymium
magnet 12" speakers available that could lighten
the total weight by 50 ounces or so... i just
swapped an Eminence 12" basslite into one cabinet
(for a Peavey Widow) and am pleased with the results
in Europe you also have Morel, i think, which is
a high end MI speaker maker with a lot of Neo models
Ciao
Ventura
ps: a Tube is a Tube is a Tube, but you do have
relatively local tube manufacturing in Russia,
so you might as well use Sovtek or whatever they
brand them... there are no American made tubes
anymore (and a lot of the equipment went to China)
john
"ciao.accordion" <ciao.ac...@verizon.net> wrote in message
news:%Pjgm.1728$Jg....@nwrddc01.gnilink.net...
> hey Viktor,
>
> yeah, just ignore him...
>
Obviously, you are the smartest KID around your block
> > Ciao
>
> Ventura
Viktor
So I have been playing a lot on the new setup (Sennheiser / Musictech
MT-04 and Traynor K4 amp), and Im very very pleased.
Now I would like to change the MT-04 system to a stereo setup. In this
way I can send the treble side to the preamp with tubes, and the bass-
side to another preamp (solid state) - and change the sound
independantly.
I AM sorry, but I dont get the technological correct way of showing
the setup, so I have made a drawing of how the wires are put together
right now.
http://www.flickr.com/photos/31544092@N06/3937321948/
I hope it makes sence!
In this way the battery is disconected when a mono jack is connected.
If I was to change the setup with a stereo jack output, I guess the
disconnection of the battery would not work, and I would have to put a
on/off button on instead?
But listening to your advices, I guess using to mono plugs instead, is
a good solution.
So can I just split up the wires comming from the two pots into two
jack-outs, and split the black wire from battery into the two middle
rings on both jack-outs?
Would that work, or is there a better solution?
Thanks again and again :-)
- Viktor
Viktor
connected.
Sorry, of course: In this way the battery is connected when a mono
jack is connected.
Viktor
> jack-outs, and split the black wire from battery into the two middle
> rings on both jack-outs?
> Would that work, or is there a better solution?
Did it, and it works :-)
ciao.accordion
good
now your next step is Wireless...
(a pair of X2 or XDS Plus which have 5 channels
or a set of Senn's the 4 or 16 channel models)
BTW if you send me a pic or link to
something with you and the Tiger, i'll
forward it to the Lady who designed it
bet she'd get a kick out of seeing someone
enjoying and using one Professionally after
all these years
you have my e-mail
ciao
Ventura
João
I really linked to find a place to discuss these things...
I`m planning in buiding from scratch my own mic system for my accordion and I`m studying the possibillities.
I was wondering if anyone knows anything like this system that a verry good accordion repairer from the South of Brazil, from whom I bougnt my accordion.
He puts a strage metal or plastic capsule to reduce feedback.
There are pictures on his website. Unfortunattelly it is in flash, so there isnt a direct hyperlink.
go to http://www.oficinaranchonovo.com.br/, hover through "Serviços" and click on "Micronofação (captação)".
On the last 3 pictures you can see that the mics have an outter shell or capsule that appears from the outside of the instrument.
He said its for reducing feedback, but does anyone know what that is, or what he did?
Thank you
Ike Milligan
"João" <tragt...@gmail.com> wrote in message
news:1e41fb68-1e71-40c9...@googlegroups.com...
values of the resistor and capacitor are chosen to filter out a specific
frequency. Like 15K Hz for example. That would need to be the frequency of
the feedback tone. you would put the RC in parallel, then that circuit in
series with the output. You would need to determine the value in microfarads
and ohms of the RC. This is basically whjat was done, but it might be an
oversimplification as I am not an electronis engineer and I don't know all
the nuances. I think with a modern condenser mic system you would not need
this filter.
Ike Milligan
new subject line.
Excelsior960
the frequency response is fairly even 20 - 20,000 Hertz
which is far higher than needed for Accordion reeds
Higher frequencies tend to more quickly echo and feedback
in a sound loop (practical usage, performance situations)
so s simple "Filter" that "rolls off" what the Mic element
can pickup (say, limiting the response to 20 - 12,000 Htz)
may also limit feedback, but only by limiting the
"opportunity" for it - so to say a simple tone control
circuit (as the fella kinda claimed) is a feedback control
is dis-ingenuous
to limit feedback, truly, using these elements in and on
an Accordion, you would be best to first select elements
that are highly directional, which naturally resist the
feedback loop, and also to mount them in such a way that
they catch the maximum amount of reed sound while being
protected from the reedsound that reflects back IN to the
Accordion, and hence when picked up causing a feedback loop.
This is why, as many of you know who have seen me, I tend
to prefer mounting Mic elements into "rails" that are mounted
on the outside of the grille - the rails acting as good sound
collectors from the direction of the grille out - while forcing
the reflected sound to not only pass back into the grille, but
then to bounce back out, up, and into the rail.
if mounting elements inside the shell, judicious use of small
pieces of foam as sound dams, and careful use of Silicon Caulk,
can allow you to create tiny "Foxholes" around the elements that
will help resist any sound waves coming at an angle off the
elements axis
the other thing that helps control feedback is to amplify your
Bass and treble in two separate channels of your Mixer... as i've
stressed many times in the past - the bass frequencies should NEVER
have "Reverb" or echo of any type applied - but you may want reverb
on the treble. Bass tone feedback loops can roll for long
periods of time before you really "notice" them, but they are
muddying up your sound out there in the audience something fierce.
ciao
Ventura
João
I'll post my repply on a new topic as suggested Ike. I'll call the subject: "Strategies to Reduce Accordion Feedback"
jcan...@gmail.com
> Hello! First time for me here.
>
> I play in a rockband. Very loud - and of course I have a lot of
> feedback-problems - also in rehearsal-studio.
>
> My former accordion was a Hohner Bravo III 96, where I installed
> THOMANN ACM-01 accordion pickup system. Cheap, but worked quite well:
> http://www.thomann.de/gb/thomann_acm01.htm
>
> I put some leather inside the case of the accordion to take away some
> of the resonance, which I think helped a little regarding feedback.
>
> Then I fell in love with a TIGER Combo´cordion from the sixties, and
> bought it through EBAY:
> Treble-side:
> http://www.flickr.com/photos/31544092@N06/3704893546/in/set-72157621052310113/
> Bass/Chorus-side:
> http://www.flickr.com/photos/31544092@N06/3704083637/in/set-72157621052310113/
>
> It came with an original crystal(?) microphone placed in the bellows.
> Unfortunately the amplified sound was very sharp, and lots of
> feedback.
>
> Therefore I went to an accordion-dealer, and he suggested the
> Microtech/Sennheiser MT-04 system, which he installed.
>
> In the following pictures you can se how the system was installed.
>
> Inside the treble side:
> http://www.flickr.com/photos/31544092@N06/3704084089/in/set-72157621052310113/
>
> Inside the bass/chorus side:
> http://www.flickr.com/photos/31544092@N06/3704083261/in/set-72157621052310113/
>
> I still have feedback-issues. Even though the sound is much better,
> the Thomann system actually worked better regarding feedback. I also
> experience a phase-problem, since the treble-side strangely has more
> feedback when the bass/chorus-side is turned down.
>
> Has my accordion dealer put the mike correctly on the bass/chorus-
> side?
> Close-up in the bass/chorus-side
> http://www.flickr.com/photos/31544092@N06/3704082337/in/set-72157621052310113/
>
> Has anyone here got experience with installing internal microphones?
> Is it maybe an idea to put a piece of foam weatherstrip(?) under the
> circuit board to act as a sound damper, as John C. writes here:
> http://groups.google.com/group/rec.music.makers.squeezebox/msg/7b99a8cfe97abb6b?hl=en&dmode=source
>
> Any other suggestions are greatly appreciated!!!
>
> Viktor (Copenhagen, Denmark)
Hi All, Ive just recently read all the talk about feedback and thought I'd let you know about an accordion mike system that has been designed by a friend of mine in Australia. He is Peter Anderson, a very good accordion technician and tuner who goes by the name "Captain Accordion". His system is virtually feedback free. Here's a link to his website - http://www.members.optusnet.com.au/capt.accordion/ - Cheers John - www.johnandprimrose.com