sound transforming like Electro Harmonix B9/C9/Mel9/Key9 do
  • Hello all,

    This is my first post here :) Though I have been playing with audulus for years - Great audio platform to experience!

    Recently I have been interested in morphing my guitar & cello sound into different timbre.
    Other than using pitch-to-MIDI methods, Some recent Electro Harmonix pedals seem to do it very nicely.
    http://www.ehx.com/products/b9
    I am recently trying to do it with audulus using different ways like fundamental frequency extraction (the guitar synth post here also gave me some inspiration) + compressor + pitch shifter + ADSR but haven't achieve nice result yet,
    Wondering if there's other approaches, so I put this topic here to see if anyone also interested in this :)

    Looking forward to exchange more ideas with guys here!

    Cheers,
    Brian
  • >fundamental frequency extraction

    How does that work?
  • I referenced the patch from this post: http://forum.audulus.com/discussion/103/guitar-synth-patch/p1
    While the patch outputs the pitch frequency value, I started my modification from there, using band pass filter and start from the filter output (after a level node controlled by env follower). Maybe not perfect, but it's the rough idea I got so far.
  • Ah, @biminiroad said there was a way to open Audulus 2 patches but I haven't the foggiest. The idea is to find the band with the most action and set that to output a frequency value somehow?

    Edit: Also I checked out that link! Crazy that that works so well.
  • @RobertSyrett - there is not a way to open Audulus 2 patches - we tried to implement it, but couldn't get it to work. @wangpy Here's a guitar synth tutorial: http://forum.audulus.com/discussion/1059/how-to-use-nodes-zero-cross-node-guitorgan-guitar-synthesizer#Item_1
  • Hi there @wangpy! Strangely enough I'm working on processing my cello in a related way!

    I'm at a very early stage myself, but processing both the output of the zero cross, and the envelope follower through slew helps to smooth out a lot of the weirdness stemming from complex audio. I was hunting for a "threshold" type control when I found this post, so thanks to @biminiroad (as ever) for the patch.

    I was interested to read the post you linked to, involving filtering the zero-cross output. Perhaps Bimini, @Taylor or someone could clarify the signal path (as the old patches are now inaccessible). My interpretation audio in>bandpass filter (high resonance)>zero cross>cut off of bandpass filter (the same filter?) as well as onward to control oscillators etc. Is this correct?

    I'll post results as I get them!

    Have you got any further with your experiments, wangpy?
  • @audioneiromancer - Check out the attached patch - I call it "guitar synth" but it can work for any stringed instruments - it will probably even work better with cello because the fundamental frequencies are stronger than an electric guitar (which makes for better pitch-tracking).
    Guitar Synth Start.audulus
    5K
  • Hi @biminiroad, thanks for getting in touch! I'd got to a stage very similar to what you posted, but the speed of the envelope follower and zeero cross mean that I end up with amplitude modulation, and a lot of noisey frequency "errors".

    I sketched out a 0.2 version of my system, but I haven't had a chance to tune it yet. My current thinking is I need:

    * Negative slew on the envelope generator
    * Some sort of gating to stop noise triggering the zero-cross? With it's own slew rate/envelope

    I've not yet tried to build a negative slew, and my prototype gating is currently overly binary, resulting in its own artifacts.

    I've been using your guitar synth (for which you provided a link to the OP) and a guitar noise patch by @robertsyrett for reference and inspiration.

    I was going to attach the audio file I've been using for testing as an attachment, but mp3s aren't allowed it seems! So here's a link to the file from my NAS for reference: http://gofile.me/2M0zw/ZJxMZazdZ

    All help gratefully received, on consituent parts or the overall project, but I've not had a chance to exhaust my current design thoughts yet. Thanks in advance!