WANTED: Midi Theremin

randy rote: the synth would have to be configured use slide or portamento or have slow attack and quick release. .. or something to mask the constant re-attack of notes.

I had a discussion about this problem with the late Robert Moog back in 1997, shortly before he released his MIDI Ethervox theremin. He said that in order to be able to control a MIDI module using current MIDI technology and pitch/volume information only, a module would have to be designed that would fade each individual note in and out, seamlessly, as you changed the pitch. Notes would not be required to bend any more than one semitone up or down before the next note kicked in. 

The MIDI Ethervox has a "PITCH SMART MODE". As the left hand pulls away from the volume antenna, the amplitude of the theremin volume control signal increases, but when the volume hand reverses direction, a new MIDI note-on message is sent with a note-on velocity value equal to the last value used (which is displayed on the E'vox led screen). The note-on number is determined by the position of the right hand in relation to the pitch antenna at the instant the note-on message is generated by the left hand. 

It is a complicated system, requiring the thereminist to add a new skill to the playing technique of an instrument that is already humongously difficult to control.

"He said that in order to be able to control a MIDI module using current MIDI technology and pitch/volume information only, a module would have to be designed that would fade each individual note in and out, seamlessly, as you changed the pitch. Notes would not be required to bend any more than one semitone up or down before the next note kicked in." - Coalport

This would be true for a polyphonic instrument to be driven in a monophonic emulation mode - But its not true for a monophonic instrument.. (As the vast majority of MIDI instruments are polyphonic, I can fully understand Bob Moogs reasoning).

There are some (few) monophonic MIDI "recievers", and for these, all one needs to do is to disable note triggerring (as in, bypass / disable the envelope generators) and feed the note data and pitch (bend) data to the oscillator/s, and feed volume CC data to the VCA/s and (if wanted) the VCF/s

It is true that with the above, if one restricted pitch bend data to 7 bits, one could get slightly better than 1 cent/step, and slightly reduce the density of the MIDI stream.. but the extra byte for LSB data aint going to make much difference.. MIDI will be hard pushed to deal with the stream of CC's for both Pitch and Volume, and the note data - Running status (which speeds things up on keyboards and the like) could not be implemented as the CC messages would be predominant.

I did a fair amount of messin with MIDI and theremins when a potential investor demanded MIDI - Despite desperately needing this investment, I was not able to provide what he was requesting using standard MIDI implementation.. To make a true MIDI theremin which behaved like a theremin, required dedicated MIDI "reciever/s" were constructed, and to do the job well required at least 2 MIDI ports so that the streaming could be done in parallel.

From what I have seen of OSC, this protocol is far better suited to theremins.. But (apart from perhaps PC based) how many OSC compatable instruments are there? MIDI is popular because it is a standard across the majority of electronic musical instruments. A high speed USB like interface, with a protocol better suited to cover gestural and other controllers, could easily be implemented on modern instruments (and backward compatibility maintained with MIDI) - But I do not see this happening anytime soon (hope I am wrong!)

Fred.