Sample Slicer

[gibbles]

Hey all,

Having trouble with clicks when I use the following code, not sure if this is perhaps the best method to achieve what I'm after? I basically want to be able to cut up and rearrange a buffer, the result being read back through final bufrd. Sorry if this post is a little incoherent, long day at work!

~index = Buffer.alloc(s,512,bufnum:1); //index buffer
~steps = Array.fill(16,{16.rand}) //array of steps
~steps.plot; //take a peek
(
~scramble = { //function scrambles array further and fills buffer with steps
~size = 512/16;
~steps = ~steps.scramble;
~steps.do({|item,i|
item = item.min(16);
~index.setn(i*(~size), Array.fill(~size,{|j| ((item*~size) + j/512)}))
});
}
)

~scramble.value;
~index.plot;
~sound = Buffer.read(s,"sounds/a11wlk01.wav",bufnum:2)

(SynthDef(\phizzing,{|index_buf,sound_buf,rate=2.5|
var index_frames,snd_frames,phasor,bufrd,sound;
index_frames = BufFrames.kr(index_buf);
snd_frames = BufFrames.kr(2);
phasor = Phasor.ar(0,index_frames/(rate*BufSampleRate.kr(1)),0,index_frames);
bufrd = BufRd.ar(1,index_buf,phasor,1,4);
sound = BufRd.ar(1,sound_buf,bufrd*snd_frames);
Out.ar(0,(sound*2.5).dup);
}).play(s,[\index_buf,~index.bufnum,\sound_buf,~sound.bufnum])
)


thanks,

gibb

[dewdrop_world]

Clicks and pops are probably the result of jumping from one part of the sound buffer to another without managing the transitions.

I don't have time this morning to rewrite the code, but the way I would handle the transitions is to use a trigger UGen (Impulse) to trigger the change from one sample to another and use that to trigger BOTH restarting sample playback from a new buffer location AND an envelope to fade in and out quickly.

The transitions can be seamless if you split the stream of triggers into two streams, which is easy using PulseDivider.

PulseDivider.kr(Impulse.kr(freq), 2, (0..1))

Then, one envelope is fading out while the other is fading in... no break for the listener.

This is probably hard for you to visualize now... tonight I can rewrite your example to illustrate what I mean.

hjh

[gibbles]

[dewdrop_world]

Weird... I posted this earlier with more comments in the code, but somehow it disappeared from the thread.

This might be confusing at first read, but ask questions and I'll try to explain.

[gibbles]

thanks, that works really quite well. I have a few questions though, if you don't mind! I haven't seen or used PulseDivider before, my understanding is that this splits my trigger into two seperate triggers each at half the time of the orignal; this is then used to trigger the envelope, right? The part I'm unsure about is how both envelopes get triggered, if I pass an array(PulseDivider) into the trigger arg of the env does this create two env's as a result of multichannel expansion? Also not quite sure what the PulseCount is doing.

Thanks again for the help on this one!

g.

[dewdrop_world]

OK...

PulseDivider passes through every x triggers, starting with the y'th one. If you have trig = Impulse.kr(1), PulseDivider.kr(trig, 2) outputs every other trigger starting with the first one. PulseDivider.kr(trig, 2, 1) outputs every other trigger starting with the second.

Because of multichannel expansion, PulseDivider.kr(trig, 2, (0..1)) creates a pair of PulseDividers:

[gibbles]

thanks, thats really fantastic! This is what I love about SuperCollider and what keeps me up far too late every weeknight!