Alternative to Karplus-Strong

[vladimirslepnev]

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I've discovered that you can get a Karplus-Strong like sound by simply playing a looped buffer of noise through a lowpass filter with decreasing cutoff. (The cutoff should decrease sharply at first, then more slowly over time.) There's no need to modify the buffer as you go.

Demo: https://jsfiddle.net/byrsgkv7/3/ (https://jsfiddle.net/byrsgkv7/3/) It uses a naive 4th order filter, but any other lowpass filter will work too.

Actually I like it more than K-S:

- Pitch depends only on buffer length. No need to account for filter delay, like in K-S.

- If you want to start at the 2 second mark, or run the decay backwards, you can. Unlike K-S where you must start at the beginning and move only forward.

Is this idea known? I've tried to find it online but couldn't. Any obvious next steps?

[Music Engineer]

yes, it makes sense that this should sound somewhat similar.

Is this idea known? I've tried to find it online but couldn't.

actually, it's just subtractive synthesis with a waveform defined by your noise buffer and a decay-envelope on the cutoff. you could do this with any subtractive synthesizer that allows importing single-cycle waveforms - just use a chunk of noise as your cycle. i don't think, this has (or deserves) a special name

[vladimirslepnev]

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Update: I made another demo to test if people can distinguish my algorithm from K-S. You can play a sound and then guess.

https://jsfiddle.net/egcuhna4/3/ (https://jsfiddle.net/egcuhna4/3/)

[stratum]

I couldn't see what makes noise sound tonal. After all it was low pass filtered not band pass filtered at intended harmonics and then mixed.

[vladimirslepnev]

It sounds tonal because I'm playing a fixed length buffer of noise over and over

[JamOrigin]

Vladimir, do you have any reference or derivation on that cheap gauss function?

[vladimirslepnev]

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It's adapted from a comment by user "sellibitze" in this Reddit discussion: https://www.reddit.com/r/DSP/comments/b ... ss_filter/ (https://www.reddit.com/r/DSP/comments/b235ac/implementing_a_sweepable_gaussian_lowpass_filter/)

[faxinadu]

really nice mate, i like your approach's sound more than the k-s sound, or at the very least this is a cool implementation to have as an option for an osc to switch between, i have been experimenting with something somewhat similar, but didn't get clean results like you did. maybe this gives motivation to go back to it. thanks for sharing.