hello,

i really twist my mind over this for a longer time... i tried many different buildups but nothing worked so far

this is what i did:
i built a very simple patch of a selfcontrolled feedback in pd

the things i use:
-macbook pro
-pd
-2 piezos (mics) soldered on a cables with jacks
-metalplate

a piezo:

so i attached the 2 piezos on the metalplate, plug one jack in the line in, one in the line out and start the patch.

theres one piezo used as a mic and one as a loudspeaker (together with the object) both are attached on the same metalplate.

the circle is closed... there is a feedbackloop that goes through the object and through my computer.

when i talk or make other noises i can feed the feedbackloop...

the pd patch controls the feedback so it wouldnt grow to much, the aim is to get the larsen tones:

http://en.wikipedia.org/wiki/Audio_feedback

....this works really fine with my macbook pro because of its build in headamplifier.

i really can hear my voice and all the high frequented noise i make (the piezos have got a spectrum of 2900 ± 500 Hz)

now i want to plug more of these together. for this i use a m-audio 1814.
but i just hear a feedback, no voice or noises. sounds like they were cutted out.

i tried:
-the mic preamp
-the headphoneamp (it has got 2)
-an external booster
-different buffersizes with jackpilot
-different delays

NOTHING...

whats so special about the macbook preamp ? or is m-audio just lame ?

greetz...

well, here is the controlpart of the patch..

greetz...

http://www.pdpatchrepo.info/hurleur/feedbackcontrol.pd

I think you could possibly do this more simply. You seem to be going a long way around using a [lop~] as a gain control.

Have you a recording of the sounds it makes? (with the piezos)

cheers,
andy

thanks alot...

i found out what the problem was, its the piezo (its too undynamical for this)

when i use a real mic for input instead of a piezo it works well

i realized this, when i tried to record the feedback......

thanks for the tip master obiwan.....

hey dieter laser

you can get a much better range out of those piezos if you run them through a direct box and a nice mic pre. I've noticed very very significant increase with mine this way.

there is also these to try:

http://www.windworld.com/products/msipu.htm

slightly noisey but they are very cool; they have a much better frequency response than the buzzer type piezos.

I have also noticed that the powerbooks and macbooks make a very special kind of distorion when you overload the ADC/DAC's. you might be able to reproduce that type of sound with something like a preamp circuit kit; the kind you can find at hobby stores / websites.

hey thanks again... i really love u guys

hey myo,
so u boosted the signal and also used a di-box to get the ckrakles out...

i will try that when i get one....

i have some piezos who react by 2900 hz ... + - 500 hz
and some tiny ones for higher frequencies

hope this works better and they response more effectual

...i will let u know