Hi forum.

Not really sure how to explain what is going on in my patch. Can someone please download and try to reproduce what is happening to me?

I made this patch that uses a [delwrite~] and [vd~] combo to do pitch shifting. All is fine 'n' dandy. When I try to add feedback, it sounds really cool. Then, after about 30 seconds of messing around, I hear a strange sound. Kinda like that weird noise when a signal goes past the Nyquist limit and begins to "bounce back" (at least, I think that's the sound). At first I didn't know what was going on, but I can confirm by looking at the vu~ meter that --somehow-- something is feeding back at a ratio greater than 1 and slowly gaining volume until I am forced to mute everything.

Keep in mind this takes like 30 seconds to develop, but when it does, it's horrendous.

Please help!
pitchshift.pd

@rjp9 Hello "rp"
I have looked at your patch from time to time......... and of course there are two feedback loops if you are using a laptop microphone..... the acoustic one > the microphone........ and the electronic one that gives (a part of) the echoes by design. Adding a whole "1" signal to another at the outputs of the [vd~] objects risks putting your patch into "positive" feedback. "1" is 0db= max level in Pd.
Obviously, depending on the latency of the soundcard and the media/audiosettings that you have the delays will be modified.
Until your patch sinks (not really the word)......."flies" into chronic feedback..... the sound is really "great" (as you say)......

If you were to use [clip~] you could contain the build-up........ but?........... Using "magic glass" I saw audio values into the tens of thousands at the outputs of the [vd~] objects.......not good.

I think you should play around with [limiter~] to get closer to the effect that you are looking for.
I have included it in your patch to contain the "disastrous" feedback, but it destroys the effect I think, Maybe not? That is because it acts in this case (with these parameters) as a "leveller".
feedback.pd

However [limiter~] is actually a compressor with attack, delay, ratio etc. and maybe you can insert it in certain places and get the perfection that you are seeking?

David.