[PD] Non-transposing delay

[Roman Haefeli]

On Thu, 2008-06-05 at 22:36 +0100, Andy Farnell wrote:
> 
> And conversely, a delay buffer with a ordinary movable read point
> (which is what I guess  you really want in this case) will always
> cause a click since there's no reason why jumps between arbitrary 
> samples will be smooth. Of course there will be no trasposition
> since the read location changes instead of the rate.
> 
> Transposition may be desirable, but clicks rarely are. As it
> stands you can either have smoothness with transposition, or 
> no transposition and clicks.

iirc, there is a technique described in millers book, which i don't
recall the name of, which is used to avoid discontinuities, when jumping
from one to another time point in an audio stream. this is achieved by
adding a ramp to the signal, that smoothes out the difference between
the samples at the jump. i used this technique to create clickless loops
with arbitrary length. i assume, it would also work for a
non-continuous, but clickfree changeable delay (without transposition). 

however, if jamie wants it to be continuous, then probably the technique
as shown in 3.audio.examples/I07.phase.vocoder.pd could be used, which
is very cpu-time consuming, though.

roman




		
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