[PD] Help - filters & band limited oscillators!

David Powers cyborgk at gmail.com
Wed Mar 14 19:38:04 CET 2007

On 3/14/07, Roman Haefeli <reduzierer at yahoo.de> wrote:
> On Wed, 2007-03-14 at 04:46 -0600, David Powers wrote:
> > I found those, but are they really band-limited? I'm fairly sure I
> > hear ugly digital artifacts in the saw.
> what artifacts? can you elaborate that a bit more?

Hi, listen at exactly 474 hz, and tell me if you think something sound
funny to you, I guess... (the oscillators in my example are the same
ones in the original example. Sometimes there's table not found errors
in PD though).

Oh and fyi I've looked in two dif versions of PD on my hard drive,
highest example number is "G.09.pitchshift.pd" ... PD I'm running is
0.39-2 I guess... I think I'm out of town, but thanks for showing me
Miller's examples. For whatever reason I did not have the "H" "I" and
"J" patches at all in any PD on my PC.

Anyway I guess this is "good enough" for demo purposes, here's my
subtractive workshop patch attached. Digital artifacts are VERY
noticable though. Of course filtering helps a lot ... though I think
[moog~] might have problems of its own. I wish I had time to
understand what IEM filter would give something like a nice classic
analog low pass ...

I will do a/b in pure data soon, so you can see / hear the oscillator
and filter differences I mention. I believe my beloved ASynth uses the
minBLEP technique, I don't understand it but I wonder if it can be
applied in PD by some more math competent person?

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