[chuck-users] delay times of STK delays seem to be 1 sample off?

Kassen signal.automatique at gmail.com
Sat Mar 1 19:54:04 EST 2008

On 01/03/2008, volker böhm <vboehm at gmx.ch> wrote:

thanks for your answer, kassen.
> you have a good point here. i'm a lousy chucker and simply needed
> some feedback with the delay ugens.
> but yes, it can't work like this - at least not correctly.

Well, now, "lousy chucker" is really quite exaggerated. Calculation order
and so on is really a quite advanced subject that nobody notices until it
mysterious mucks everything up. At least it's predictable in most practical
ChucK situations which can save a lot of noise compared to some other

I'd say you are a good listener instead, I might've missed why things were
out of tune myself. :¬)

...in fact, now that I think of it, I might've missed this in some of my own
code, I could probably tighten up a rhythmical delay I use.

but what did confuse me in the first place was that i had already
> tried to add a feedback path in the ugen source, only to find, that
> the timing still wasn't right. that led me to the conclusion that
> there must be something wrong with the way the delay time is
> calculated - sorry that was a little fast. i did some further tests
> and delay times are indeed set correctly.
> the problem i ran into, is related to the "Writing before reading
> allows delays from 0 to length-1" - approach, which is stated in the
> source.
> i changed the order of write and read, added a feedback parameter and
> everything is fine.

So, if I get this right, you made sure the delay now works at it's set
length for both feedback and straight output?

That would be quite a valuable  addition if you'd submit it (not sure if
there's a official process for this). At any rate this phenomenon could
stand some attention in the manual because any system using feedback will
run into this. Often the Z-1 function inherent in the feedback is actually
beneficial and useful but we should probably document that it's there, where
it is exactly and how it will affect things.

Glad to have been of help. I hope you'll share your fix, sounds like a
solution that would be good for everyone.

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