My Karplus-Strong work-in-progress Guitar Strummer patch

I thought I’d share a video of the patch I am working on for the Organelle. I’ve only had the Organelle for less than a week and am completely new to Pure Data, so of course I thought I’d start with the hard stuff!

I noticed there wasn’t any Karplus-Strong based patches for the Organelle (that I could find) so I found an existing Pure Data patch and have been trying to modify it to work with the Organelle (I reached out earlier for help with this in another post.)

The patch simulates strumming a guitar, and there is still a lot wrong with this patch that is not working as it should, so before I upload the patch itself, I want to try and dig deeper to see if I can progress it further along…

Issues that need resolving:

  1. The “Strummer” isn’t working as it does in the original Pd patch.
  2. There is a Noise Burst happening when the patch isn’t playing (probably needs a “note off” command?)
  3. The Decay knob is not working as it should, it only causes excessive noise, so I’ve disconnected it in the patch temporarily.
  4. Need to add the ability to play individual notes from the keyboard when the Strummer is not engaged.

EDIT: Updated video…


Even with the issues you’re having this sounds like a killer patch!

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Thank you! Working on it…

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Ok, here is the updated video to my Karplus-Strong based Guitar Strummer patch for the Organelle. I did a little explaining on what the Organelle is for users of my Youtube Channel who don’t know (I get a lot questions from people asking “how is it compared to an OP-1” but that’s really apples vs oranges!)

All issues have been fixed. There are still a couple of things I want to add, so as of this video, the patch is at a Beta version of 0.9.7 - but for those of you who wish to try it out, the download link to the patch itself is in the description of the video. Music starts at the 4:20 mark. And thanks once again to @iquestionshard and @Fuurthur for the help on the fixes!

(also, sorry there are two threads for this, it made sense at the time, but if the Mods want to merge the threads, feel free!)


Awesome patch !
IMO it needs some more love. I’ll modify a few things in the next weeks if i find the time.

Parameters and their names. They’re weird

  • Strum speed is high when turned left, and slow when turned right. it should be reversed and from 0 to 100. Has the 100% any useful meaning ?

  • Width should be renamed “Pluck” or something close.

  • Decay goes from 0.9 but not 0.9 to 1 but not 1. Make it go from 0 to 100 and scale it.

  • Cutoff is ok, but it’s also changing the decay of the notes… I don’t have any other idea for this one. “Palm mute” ?

Make the up strum optional on note release, or make it work only on the last note if it’s released less than 1s after it’s been pressed (don’t know about this one :stuck_out_tongue: )

REAL SEQUENCER§§§ Just throw in the classic organelle sequencer instead of the melody generator.

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Thanks! And it needs a LOT more love…

The thing is, with an algorithm like Karplus-Strong, which is working with filtered delay lines, the Width/Decay/Cutoff are all working together on the “effect”. Think of this as an effects processor for a burst of noise (which is exactly what it is) when you widen that noise, you hear more of it (the Width) and when you open the Cutoff, you are allowing more of the trails of the delay line through while brightening the Resonance, etc. That’s why those are named the way they are. Also, I did try the Decay at 0-100, but it messes up the algorithm between the Width and Cutoff.

As for the Strum Speed, yeah, it really should be called “Strum Type” or something… the “100%” has no real useful meaning; completely arbitrary.

But, yes, one of the long term goals is to let you play any melody with a sequencer. More immediate goal is to be able to transpose the melody with the keyboard.

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Incredible patch :pray::pray::pray::pray::pray:

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Thank you, I really appreciate that!

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