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Smoothing out pitch change in delay feedback

August 29, 2012 | 12:31 pm

Hello everybody,

I’m not new to max/msp – and thought I had a working brain, but apparently not…

I’m looking for a way to make a pitch-change in a delay feedback run silkily smooth.

It’s a simple patch, but despite trying every method of pitch shift and delay size, there is always a ‘pulse’ in the delay (especially noticeable when the sound file stops….)

Is there a better way to do this – or am I always going to be hitting a window-size issue which makes this pulse happen?

The desired effect it a constant cascade of falling pitches, but totally smooth.

Thanks in advance….

Lee Morgan

Attachments:
  1. pitchfaller.maxpat

August 29, 2012 | 12:49 pm

Hi.

Try ej.vdb~ : http://www.e–j.com/?page_id=76

hth
aa


August 29, 2012 | 2:34 pm

Thanks Andrea – happy to get those tools, but it doesn’t seem any better than tapin/out in this particular patch.

I’m about to try 2 delays with phasor to swap between the two, and fiddling with delay times and fft sizes, overlapping sizes….but maybe that’s a dead end?

Lee


August 29, 2012 | 6:03 pm

Hi Lee
have you checked out our "good buddy Sam" at Delicious MaxMSP on youtube? He has a good collection of both fun and didactic tutorials, including delay-based pitch variation; I’m sure you’ll find something you can hack.

Brendan


August 29, 2012 | 7:18 pm

Yes….but it’s not really delay-based pitch shifting I’m trying to do, it’s combining a delay with pitch-shiftiing on a feedback loop that I’m trying to do….the delay itself is (and I think needs to stay) static…


August 30, 2012 | 4:52 pm

I think you’re running into the reality of digital audio. Each individual sample has no pitch; pitch is an emergent property of a group of samples. You can’t really shift the pitch until you’ve collected a group of samples.

I made patch called harm-gran~ in the CNMAT downloads that does pitch shifting on relatively short windows. But there are still audible artifacts. gizmo~/pfft~ also imposes it’s own delay. In the time domain, there really is no pitch shift without some time shift.

http://cnmat.berkeley.edu/downloads


August 30, 2012 | 8:37 pm

Well now you see, this is why I love max/msp and it’s community: helpful, unpatronizing explanations…..we all learn, and move on. Thanks doc!


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