AVR synth noises

[Gordonjcp]

We all like a little bit of Amen break, don't we?  Now can you imagine resampling to 11.7kHz 8-bit, and sticking it through a resonant filter?

You don't need to:

http://www.gjcp.net/~gordonjcp/ameniser.ogg

[Gordonjcp]

And another:

http://www.gjcp.net/~gordonjcp/mp3s/glitchamen.ogg

I really could do with some dedicated Arduino-using glitch lunatics to help me test this stuff.

[Circuitbenders]

I'm still not entirely sure what you're doing with this thing.

Is the amen sampled into the Arduino somehow and then processed, or is this processing an audio input?

[Gordonjcp]

Basically I took an Amen break, chopped out one bar, resampled to around 21kHz, and converted to 8-bit unsigned.  Then the code plays back the sample in eight slices mapped across keys, giving a crude beatslicer.  Thrown in there is some mangling of the pointer into memory for where to get the next sample, so you can get those traditional shorted-address-line bends.

I've just discovered that I've clobbered the version I uploaded, so I'll stick together another page with full instructions on how to set it all up and how to convert your own samples.

[Timodon]

Second one sounds really cool Gordon.

So it's like a hardware version of livecut/ supatrigger with some added filtery/ glitchiness?

[Gordonjcp]

I don't know what those are...

[Timodon]

They're the plug-ins that completely destroyed the mystique of drum 'n bass when I was shown them.

I've just noticed you used the word "beatslicer" in an earlier post. I guess you could described them as that - so you kind of answered my question already. How's it work then eh?

[Gordonjcp]

First off, I promised days ago that I'd post the source and I will, just as soon as I tidy it up and make it safe and accessible for others.

Right, it works like this:  You've got a sample that fits in around 24k of memory.  It's an 8-bit low-samplerate sample, so pretty crunchy.  Now, the MIDI notes are mapped so that each one plays a slice 3K long.  If you play each slice in sequence at the right speed you get the original beat.  You can speed it up, and they overlap slightly - this works for a few BPM up without making it sound "stumbly", and it works for a few BPM slower without the gaps between being noticable - a bit of reverb will mask them anyway.  You can play the slices out of sequence for that traditional breakcore broken beat stuff, snare rinses and so on.
Okay but what about the glitchyness?  Well the sample playback is done by a counter.  Load the counter with the start address of the sample, and when it reaches start+3k stop playback.  Simple.  To get the glitching, you bitwise AND the address counter with a bitmask.  If you AND it with 0x0f then it will always play the first sample of a block of 16, 16 times in a row.  Mask off 0x01 and it will play all the even-numbered samples twice.  Mask off 0x80 and it will play a block of 127 samples twice giving a stutter effect.  There are two parameters, bitmask and shift, which work to give you a total of about 1000 different bitmasks you can apply to the address counter.  Some sound musically useful, some just make clicky noises.  You have to experiment to find the good bits.

[merry1shah]

Your post is truly sensational as always. Great work. Keep it up. Looking forward to reading some more of your forum postings.