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SloBo - Bowed Strings synth

Posted: Fri Dec 01, 2017 4:27 am
by cube48
SloBo - a synth made purely with SunVox modules, no samples involved. It's my personal study case of synthesizing a raw approximation of bowed instruments and learning about the articulation techniques of cellos, violins & Co. It's called SloBo because as of now it allows only relatively slow bowing articulation. Future versions or derivations might include other playing styles (need to dig deeper into the topic).

Important note: The patches below were not tested with any traditional MIDI keyboard. They were designed for Linnstrument in first place. They expect ModWheel and Aftertouch action for successful expression.

ModWheel - sets the vibrato speed, from rather slow to faster, both set by ear to sound as human as possible :)
Aftertouch - tries to imitate harder bowing

While playing a single voice, you should avoid playing legato otherwise it will sound too synthetic while 'gliding' between notes, so always lift one finger before pushing another note. But this prevents faster playing.

Ideally you would play the 4 voices patch, each voice on it's own channel (1-4). This will give you smoother overlaps between notes and will sound more natural.

All resources about cello/violin synthesis I've studied so far are having one thing in common, they all state that the key is the playing technique. And it seems to be true. Sometimes these patches can sound pretty acceptable, other times, when screwing the technique, they simply sound too artificial. Anyway, SunVox is so much fun! Thank you Alex for the latest update which opens the MPE world!
SunVox_SloBo_guts.png (43.41 KiB) Viewed 2342 times
Technical explanation of the patch
Glide input is optimized for Linnstrument and it's 24 semitones PitchBend range (Pitch scale 40% in Glide module corresponds to 24 semitones of LS). Pitch is mapped to actual PitchBend MIDI input. Saw wave is generated by Analog Generator and goes through ModWheel controlled Vibrato into WaveShaper to get some more grit and then into 'resonator' section which is a little chain of 3 feedback loops with filters. All-pass is used to introduce some phase-shift of the whole frequency band. Central Amplifier is controlled by Pressure (Aftertouch) for certain level of loudness expression, followed by two more filters (LP&HP) with tiny amount of fast random LFO on Frequency to make the sound less sterile. Next is the Band-pass filter bank which more or less defines the sound of the cello body. Frequencies are taken over from the SOS Article on Bowed-string Synthesis. Filter bank goes to Hard Limiter which gives the sound harder edges (again controlled by Pressure) to get this 'scrubing' of bow sort of impression. At the end is simple set of Compressor, Exciter and Reverb.

cube48 SloBo.sunsynth
(43.97 KiB) Downloaded 495 times
SloBower.sunvox - 4 voice patch optimized for Linnstument (MIDI Ch 1-4).