[PD] Smooth looping

ypatios ypatios at gmail.com
Fri Apr 23 22:49:19 CEST 2010

As I understand and as Matt already wrote, you wanted a transposition of the
phasor~'s frequency (which would change the frequency of the loop but not
the sample content), but instead you did the classic
up/downsampling-of-the-soundsample transposition.
(The "distortion" you get is due to the difference in spectral content,
which should be richer as you transpose upwards since you read a longer
portion of the sample.
Also, the end of the loop changes which could mean a harder discontinuity.)

I tried to fix the transposition and I also added an offset in the audio
path before tabread4~ that corresponds to the beginning of the loop.

And I'm sure you've already figured everything out, long before you got our


On 23 April 2010 20:27, Frank Barknecht <fbar at footils.org> wrote:

> Hi,
> not related to the thread on smoother audio in Pd, I am struggling with
> doing a smooth
> loop player for data stored in tables.
> One building block for this is attached: It is a simple tabread4~ lookup
> that
> should loop over a configurable section of a table and play it back with
> various frequencies.
> As you'll easily see, I use a
>  [phasor~]
>  |
>  [*~ loopsize]
>  |
>  [+~ loopstart]
>  |
>  [tabread4~ table]
> idiom here. Now I would like to avoid enveloping the rewind sections, so I
> built an elaborate mechanism to set the loop points as good as possible by
> hand. Test sections let you load a sample or try to find the smooth loop
> points
> inside of a sine-wave table graphically.
> Now my problem is, that even when I have found a nice and smooth sounding
> loop
> section, as soon as I start to change the frequency played (with the "pd
> transpose" things), the sound gets very distorted.
> I'm puzzled: Shouldn't the tabread4~ interpolate correctly in this case?
>  Any
> help or explanation is appreciated. (Except anything involving crossfades:
> I
> know I could do that and I guess I also know how.)
> Ciao
> --
>  Frank Barknecht            Do You RjDj.me?          _ ______footils.org__
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