Using #SonicPi Free Software, was able to emulate the “Michael Brecker Effect” pioneered by Robby Kilgore: http://robbykilgore.com/?p=19

Here’s my code:
https://gist.github.com/Enkerli/f0999b30ac2249af33007c765ad37387

An example:
https://vimeo.com/214204872

#ArtWithOpenSource /cc @eylul

@Enkerli Going deeper in the Kilgore link there is his hardware version in Arduino. Great way to get the function off the PC screen and into a single function box.
@Stringbender Right. But #RasPi is my “Golden Hammer” and it can work headless. There are great #Arduino projects but #SonicPi makes more sense to me.
My plan is to run a script like this from a headless Raspberry Pi with the #pisound HAT. Might use sensors later on.
@Enkerli The options for manifesting the same rotating harmonies principles on such different types of system, are inspiring. I believe it would work on Hollyhock too, using built-in modules and maybe some glue logic patches to fill the gaps. Next time I remind myself how Hollyhock works it will be tempting to make a rack for that. Putting a midi guitar through it could be interesting.
@Stringbender Precisely! Many options to accomplish the same thing. #TIMTOWtDI
And any instrumentalist could have fun with this.
One commercial solution is Johan Looijenga’s Max patch:
http://www.johanlooijenga.com/tools/5-apps/45-version3.html
ewiVoicing is Mac-only commercial freeware.
http://www.i-yanase.com/en_/page2/page8/index.html
@Stringbender To me, creating it in a few lines of Sonic Pi opens neat possibilities. It's like one of those learning projects. Simple enough to be encouraging, flexible enough to allow for further integration, and fun enough to be engaging.
@Stringbender Tried to figure out a way to make something similar in MainStage (Logic Pro X), but it sounded a bit too complicated and my only macOS device is a Mac mini, not ideal for stage performance… or busking.
My ultimate dream of an all-in-one device is a wind controller which allows for different harmonization patterns and does MIDI over Bluetooth.
@Enkerli Tried some interesting VST modules a while back which edge towards algorithmic harmonisation and auto- composition. Filtered them down to a few that were potentially useful to me.
There is also Soundhelix, a way of defining variation in arrangements with controlled randomness. Another heavy learning curve there - blogged it on https://medium.com/starting-with-soundhelix to help other new users
@Stringbender Curious about those VST plugins. Haven't found that many which weren't audio effects, at least among the free ones. Will check Soundhelix, just in case. But will probably focus more and more on Sonic Pi and Pure Data, as they're more crossplatform, easy to learn, and very powerful.
(Dabbled in SuperCollider, ChucK, and Processing. Learnt a lot but SPi and Pd might be enough for me. These days.)