delays and buffers

Hi there,

when working with multitap delay patches I find the Tap pseudo UGen quite
inefficient. Compared to multiple delays, like this:

{  DelayC.ar(Impulse.ar(1), 1, { rrand(0.02, 0.12) } ! 100 ) }.play;


Tap in combination with RecordBuf or BufWr, like this:

r = Buffer.alloc(s, s.sampleRate * 1, 1);
y = { RecordBuf.ar( Impulse.ar(1), r);  Tap.ar(r, 1, { rrand(0.02, 0.12) } !
100 ) }.play;

takes around 170% of the multiple DelayC solution!!
Also, with PlayBuf ("inside" Tap) it is not possible to modulate the
delaytime, because it just sets the startPos.

When I replace Tap by BufRd, even with only one Phasor for everything, I
could modulate the delaytimes. But regarding CPU power this takes still as
much as Tap:

r = Buffer.alloc(s, s.sampleRate * 1, 1)
(
y = { var ph, smps;
ph = Phasor.ar(0,1, 0, BufFrames.ir(r));
smps = SampleRate.ir.neg;
BufWr.ar( Impulse.ar(1), r, ph, 1);
BufRd.ar(1, r, ph + ({ rrand(0.02, 0.12) * smps } ! 100), 1, 4);
}.play
)


In order to save memory one could use shared buffers, like this:

r = Buffer.alloc(s, s.sampleRate * 1, 1)
y = {  BufDelayC.ar(r, Impulse.ar(1), { rrand(0.02, 0.12) } ! 100 ) }.play

which needs almost the same amount of CPU power than DelayC.

So in the end BufDelayC seems to be for now the most efficient solution in
terms of memory usage and CPU power.
But it still needs x buffer write UGens instead of only one.

So I guess there must be be a more efficient way to implement multitap
delays in SC3. What about a pair of UGens like the ones in MaxMSP but using
shared buffers:

BufTapIn.ar(inputArray, bufnum);
BufTapOut.ar(numChannels, bufnum, delaytime, interpolation);

???
Would it be hard to implement that?

Also, I'd like to have non-interpolating Delay UGens which take just samples
instead of delaytimes, like Delay1 and Delay2.
For the construction of reverbs it would be good to also have sample based
versions for Comb and Allpass. Plus a feedback argument instead of
decaytime!

I know, Christmas is still far ....


thanks

Andre


--------------------------------------------------
Andre Bartetzki
http://www.bartetzki.de
mailto:andre@...

Tel   +49-(0)30-92375877
VoIP  +49-(0)30-38108677
Fax   +49-(0)30-38108678

Skype bartetzki
http://www.myspace.com/andrebartetzki
--------------------------------------------------



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