[PD] Help - filters & band limited oscillators!

[Roman Haefeli]

On Wed, 2007-03-14 at 12:38 -0600, David Powers wrote:
> 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...

here 474Hz sound ok, but i still could only test on my built-in card
with only 48KHz available. i will test later again on my rme at
44.1kHz. 

>  (the oscillators in my example are the same
> ones in the original example. Sometimes there's table not found errors
> in PD though).

yeah, above 16kHz. 
and also in my patch i noticed a bit of aliasing in these high area.
maybe it would be better to switch to an [osc~], cause the waveform in
the according table is a sine anyway.

my patch has still one little problem with cpu-optimaziation. i think
the best would be to split the whole frequency range in three areas:
in the low area a raw square, in the middle area the bandlimited version
and it the are, where no harmonics could be played anyway, it could
switch to an [osc~]. i'd like to put these three parts in separate
subpatches, so that the unnecessary parts could be switched of. the
problem is, when the parts are switched off, the are not in phase
anymore, when they are switched on, so at least the [tabosc4~],
[phasor~] and the [osc~] should always run, only for keeping the phase.
could that be optimized in some way? is it possible to retrieve the
phase of these objects? of course the [phasor~]  could always  run, but
is a [phasor~] cheaper than an [osc~]?

roman




		
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