Slicing a sample

Arnaud06 · Posted: Tue Jul 28, 2009 2:41 pm Post subject: Slicing a sample

Hi,

It's me again. I have a question, wich mught not be related to ChucK, but I think a can find some people here who can help me. I want to "slice" a sample, but when I do it the butcher way, it (obviously) click at each part.

I just want to learn how to cut a sample properly with ChucK's generator or analyzers.... So if anyone have a website or anything on the subject, link me Wink

Thank you !!

mrcold · Posted: Tue Jul 28, 2009 7:35 pm Post subject:

what are using to do the slicing? I've used SndBuf and did the slicing by editing the start position of the file and I didn't notice any clicking... i was slicing a beat though, so i probably wouldn't have noticed the clicking.

In any case, look up SndBuf in the documentation (look at the otf examples for usage) and then something like THIS:

44100 => buf.pos;

will start playback at sample 44100.

when the file is read into memory, you can get the total length (in samples) by reading buf.samples.

when i sliced up a beat i got the total length in samples and divided that number by 8 or 16 and then send THAT number multiplied to buf.pos, so i got 8 or 16 even slices.

if that gives you clicks, you could use a quick volume envelope to smooth out the edges of the slicing.

good luck

Arnaud06 · Posted: Wed Jul 29, 2009 1:09 am Post subject:

That is exactly what I did !! We are on the same page (like in the Bubbles melody you post, I put my melody into arrays Wink

). I thought about the enveloppe, but it works for the first part, after that the envelope doesn't reset. I use the ADSR, with KeyOn/KeyOff.

Antimon · Posted: Wed Jul 29, 2009 3:04 pm Post subject:

One thing is to try to find a position in the sample where it crosses zero, and switch there. Check out this zero crossing thingie by Kassen:

http://electro-music.com/forum/viewtopic.php?highlight=sample+zero+crossing&t=23167

Otherwise I've had fairly good results with a fast envelope, but you need two voices for that - one ramping down as the other ramps up.

/Stefan

Arnaud06 · Posted: Thu Jul 30, 2009 12:40 am Post subject:

What do you mean two voices ?

Antimon · Posted: Thu Jul 30, 2009 12:52 am Post subject:

Two SndBufs (if that's what you're using) each with an envelope, one silent and one playing. Then, when you're changing what part of the sample you're playing, you set the position on the one that is silent and do env1.keyOff(); env2.keyOn();

...

Come to think of it, maybe I misunderstand what "slice" means... do you want to change what part of the sample is playing, or do you just want to make it go quiet every now and then?

/Stefan

Kassen · Posted: Thu Jul 30, 2009 3:26 am Post subject:

Inventor · Posted: Thu Jul 30, 2009 5:08 am Post subject:

Haha LiSa LiSa LiSa! Our Alice in Wonderland character, such a dear she is! I tried to get LiSa working but couldn't understand how the read pointer worked or how it sucked in samples. Does LiSa just suck in a minute's worth of samples or does it take a minute to do that? How do you playback backwards? I want to make an accelerometer-based record scratcher for the Laptop Battle using LiSa.

Les

Antimon · Posted: Thu Jul 30, 2009 8:52 am Post subject:

Heh, yeah LiSa is a great gal. I just think that she's a bit clumsy with sound files. I know there are a couple of tricks to read in, connecting to blackhole and shuffling bits, or just piping and recording, but that's tricky enough to distract I think.

/Stefan

Arnaud06 · Posted: Fri Jul 31, 2009 10:35 am Post subject:

But... Who is LiSa ?

Antimon · Posted: Fri Jul 31, 2009 1:04 pm Post subject:

http://chuck.cs.princeton.edu/doc/program/ugen_full.html#LiSa

DrumAliens · Joined: Jul 10, 2008 Posts: 31 Location: UK Audio files: 1

Not sure if any of this helps

http://electro-music.com/forum/topic-33705.html

Arnaud06 · Posted: Sat Aug 01, 2009 10:11 am Post subject:

Oh ok, I didn't look into the UGen list, sorry Embarassed

I'm not at home right now, so I'll take a loop deep into this LiSa, and in your script DrumAliens too Wink