On Wed, 4 Jun 2008, Kjetil S. Matheussen wrote:
>
>
> On Wed, 4 Jun 2008, Kjetil S. Matheussen wrote:
>
>>
>>
>> On Wed, 4 Jun 2008, border wrote:
>>
>> > Hey (Kjetil)
>> >
>> > Dunno if I should post troubles with snd-rt here on the mailing-list or
>> > mail them directly to Kjetil, so in the meantime I'll post them here
>> > like I did before.
>> >
>> > If I run this code:
>> >
>> > ((lambda (hertz)
>> > (do ((x 1 (+ x 1)))
>> > ((> x (- (/ (/ (rte-samplerate) 2) hertz) 1)))
>> > (begin
>> > (print x)
>> > (<rt-out> 0 (* 0.5
>> > (/ 1 x)
>> > (oscil* (* hertz x)))))))
>> > 200)
>> >
>> > everything works as expected, generating a saw-wave up to the nyquist
>> > frequency on channel 0.
>> > But if I want to run the same code on channel 1, the saw-wave from
>> > channel 0 gets distorted a lot, and newly generated one is as expected.
>> > Is there an explanatino for this kind of behaviour?
>> > I have tried all kinds of volume levels, saw-wave levels, reversed the
>> > channels still the result remains.
>> > Only if I keep the number of sines generated below 40-45 then I get
>> > acceptable results (but not acceptable saw-waves).
>> >
>> > I do need the control over the different frequencies badly, otherwise I
>> > would've use another saw-wave generator probably.
>> >
>> > Thanks for looking at it.
>> >
>>
>> You are simply using too much cpu. Snd-rt doesn't tell you,
>> although it probaby should, when you use too much cpu. Instead
>> it won't run remaining queued instruments. And since instruments
>> are placed first in the scheduling queue, the instruments
>> you add first are the one not to be played. Instruments using
>> more cpu also gets a penalty, if I remember correctly, so
>> they will not be run at next block iteration, which explains
>> the distorted-like sound.
>>
>> I think this is a good example where you should use coroutines. Coroutines
>
> Just tried it. No difference in CPU use. Not surprising when thinking
> about it.
>
> You are trying to play over 200 oscillators simultaniously.
> To make that work, you probably need to avoid calling "sin" somehow.
> Supercollider is probably a better tool for this, since it
> has some very efficient oscillator generators...
>
Hold on, you can of course use faust instead. My naive first
try looks like this:
((lambda (hertz)
(do ((x 1 (+ x 1)))
((> x (- (/ (/ (rte-samplerate) 2) hertz) 1)))
(begin
(print x)
(primitive-eval `(<rt-faust> (out (* 0.5
,(/ 1 x)
(osc ,(* hertz x)))))))))
200)
but takes many minutes to compile, and only uses a little
bit less cpu than the <rt-out> version.
I'm not fluent enough in Faust to implement your routine
in Faust on the spot, but maybe someone at the Faust mailing list can
help...
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