Cycling 74 » Topic: One sample feedback delay

One sample feedback delay

danvales82 — Thu, 17 May 2012 10:57:30 +0000

Hi everyone,

I’m trying to realize a FM feedback modulation and I need to have one sample delay of my carrier signal.
If I use the delay~ object in a feedback configuration (see thee attached patch) no sound is produced.

Otherwise, using the tapin~/tapout~ system I can’t manage one sample delay because (in my opinion) the minimum appreciated delay time is 1 ms.

Are there other solutions?
Thanks to everyone

– Pasted Max Patch, click to expand. –

Daniele

Re: One sample feedback delay

commathe — Thu, 17 May 2012 11:16:44 +0000

delay~ specifies delays by samples, not sure if it goes down as low as 1 sample though.

Re: One sample feedback delay

LiamCormacGould — Thu, 17 May 2012 16:28:41 +0000

if you have MAX 6 you could do this inside gen~ it allows single sample feedback connections

Re: One sample feedback delay

danvales82 — Mon, 21 May 2012 13:41:11 +0000

Unfortunately I’m using MAX 5 and I cannot use the delay~ object in feedback configuration because in that case the sound will stop.
Is there something similar to gen~ in the previous versions of MAX 6?

Thanks to all

Re: One sample feedback delay

halsallian — Mon, 21 May 2012 15:14:55 +0000

Can you use tapin and tapout?

Re: One sample feedback delay

Christopher Dobrian — Mon, 21 May 2012 17:22:29 +0000

The minimum delay time of tapin~/tapout~ is one signal vector, and you’re correct that delay~ does not permit feedback.

The easiest way to write an algorithm requiring one sample of delay is to use gen~, but if you don’t have Max 6 then I’d suggest looking at mxj~ (or an external written in C).

Re: One sample feedback delay

JavaProgrammer — Mon, 21 May 2012 18:41:20 +0000

Edit: Incorrect solution deleted.

Re: One sample feedback delay

Floating Point — Tue, 22 May 2012 00:10:07 +0000

doesn’t send~ and receive~ create a 1 samp delay by default? or is it the non-msp-flavour send/receive?
anyway, this works:

– Pasted Max Patch, click to expand. –

btw it says max 6 but i only have max 5

Re: One sample feedback delay

Roman Thilenius — Tue, 22 May 2012 01:12:32 +0000

nope, send~ gives you/needs one vector, which is why it works for loops.

what works, in theorie, is to do a vector brake under a vector size which is as small as one sample.

what could also work for an FM operator is that you delay the feedbackloop for exactly one cycle
of the oscillator (in case the oscillator type allows that)

-110

Re: One sample feedback delay

Floating Point — Tue, 22 May 2012 07:48:05 +0000

can’t detect a vector’s delay here….

– Pasted Max Patch, click to expand. –

Re: One sample feedback delay

Owen Green — Thu, 24 May 2012 10:56:09 +0000

That’s because there’s not a feedback loop in your patch – send~ / receive~ are clever enough only to introduce the delay when a feedback condition is detected. MSP passes audio between objects in vectors, so causality dictates that the minimum possible delay in a MSP feedback loop will be sigvs samples:

– Pasted Max Patch, click to expand. –

Christopher Dobrian is correct that C/mxj~/faust/whatever or a vector size of 1 (e.g. in a poly~) is the way forward in Max 5.

Re: One sample feedback delay

Floating Point — Fri, 25 May 2012 00:16:11 +0000

Thanks for the clarification Owen– it’s a good example of the advantages of Max 6 w gen (or more precisely the disadvantages of Max 5). I guess the OP could put my send/receive ‘solution’ into a poly~ with a vector size of 1 to fix their problem as you’ve suggested.