Re: [Jack-Devel] Variable delay line problem

PrevNext  Index
DateFri, 13 Apr 2012 16:29:33 -0500
From Chris Caudle <[hidden] at chriscaudle dot org>
To[hidden] at lists dot jackaudio dot org
Follow-UpFriedrich Ewaldt Re: [Jack-Devel] Variable delay line problem
On Fri, April 13, 2012 11:52 am, Stéphane VAXELAIRE wrote:
> Thanks, I did try that, but when I do, the sine does not seem to evolve.

Maybe I suggested the division in the incorrect location.
I tried the equivalent in Octave, and it seems to work with:
cos(n/Fs*2*pi*freq)

I don't remember how operator order of precedence works in Octave, so I
also tried:
cos(2*pi*n*(freq/sample_rate))

and that also seemed to work like expected.

By work as expected, I just mean it generated cosine values of the
expected period.  I did not try to actually implement a variable delay so
that I could make a flanger in Octave code.

Are you doing any prototype code in Octave, or is everything in C?

Also, I didn't really pay attention to how you were implementing the
delay.  I had assumed you would do an interpolated delay so you can make
smooth phase adjustments.  If you are just grabbing samples from the delay
buffer, you are going to have discontinuous jumps between samples, and
that is going to sound really bad, just like having lots of under-runs
(same effect, you are just skipping over some samples and not playing
them).

-- 
Chris Caudle
PrevNext  Index

1334376807.9887_0.ltw:2,a <86ac5ffa8a67c44bbd610dec596f5050.squirrel at email dot powweb dot com>