Forums > MaxMSP

Feedback

March 21, 2009 | 7:51 pm

Hello
I’m looking for a straight forward feedback/distortion patch that I can run a line of audio through maybe with a little delay. I’ve searched around but had a hard time finding one that is fairly simple to add to my existing patch.I really like gleetchlab 3 which I found recently and their feedback but I can’t figure out how to interface it with my max objects and jitter.
thanks for your help,
jjr


March 21, 2009 | 11:14 pm

Well, while we’re waiting to hear from the hardcore-noise-artists out there, here’s some basics [delaylines->feedback->overdrive->limiter->delaylines]->limiter->mainout

as illustrated in the patch below, hope it helps:

– Pasted Max Patch, click to expand. –

i personally would swap out the omx.peaklim~ objects with auto-gain-reduction or komp of your own(unless this is the mainstay of your whole performance; i used them because they are quick and easy), see this patch in the examples folder for some ideas on limiters/compressors:
Max5/examples/effects/kompressor


March 22, 2009 | 1:45 am

thanks a lot! I’m not totally sure how it works yet but it seems really cool. Could I use this to pass say the left channel of audio through it?
best
jjr


March 22, 2009 | 6:15 am

ya, no problem, …the

subpatch is the main guts. You could replace

with whatever is the input from your patch. If you want just the left channel of audio from your input through it, you could just add your left channel of audio(from wherever) to both the left and the right input of

. That will turn your mono signal into stereo, though. If you just want mono, you can just connect something up to the left input and then connect the left output of

to both main outs. (geez… i explain things soo convolutedly now that i look back at it(sorry), but hopefully you understand)


March 22, 2009 | 6:27 am

oh… and just to explain:

and

are just UIs for the 2 limiters(one limiter in the feedback loop to keep it contained; one limiter at the main output of the entire delay/feedback patch to contain any last-stages of over-amplification). The overdrive is key in creating good distortion. It emulates the soft-clipping of old tube-style amps.
The

subpatchers are just something i like to use to change delay times without clicks and without the old-school-sci-fi-movie sounding pitch bends(not that they’re bad but i prefer to use them minimally).

Just so you can parse it out easier, it’s not complex at all when you think of it this way:
Aside from the overdrive~ object, I simply combined ‘MSP Tutorial 28: Delay Lines with Feedback’ with the help-file for tapout~(to get the click-removal), along with the help-file for the omx.peaklim~ object(to get the limiter parameter-control UserInterface subpatches). So you could easily just look through the tutorial and the helpfiles I mentioned and get a breakdown of what’s going on in further detail.

As for the general algorithm, it’s just a matter of using a limiter-type function(auto-gain-detection/reduction) over the parts of the signal which may get out of control in amplitude when playing with feedback. But there are many secrets to doing this well(try a multiband compressor instead of or along with a limiter) as well as infinite ways to manipulate the feedback loop(replace or add to the overdrive~ portion of the feedback loop with comb-filters or amp/ring-modulation, etc.). Enjoy!


Viewing 5 posts - 1 through 5 (of 5 total)