IMO, a polyphonic theremin is the wrong direction anyway.. [i](by polyphonic, I mean the ability to control several pitches independently)[/i] as one would need to have multiple hands/arms (and probably brains) to play it musically.
Having multiple pitches tracking each other is possible now with present technology - simply use CV and drive several oscillators detuned from each other.
Duophony (two seperately controllable pitches) is possible and usable - one pitch determined by hand <-> antenna distance (capacitance) and the other pitch being related to this, but being offset by the hands vertical position - as in, if the hand is alligned to the centre of the pitch antenna, both oscillators produce the same pitch, raise the hand and the 2nd oscillator pitch increases with respect to the first 'master' oscillator.. lower the hand and the pitch of the 2nd drops with respect to the master oscillator.
The above also really needs seperate volume control for each oscillator - this can be achieved by adding an axis to the volume antenna - so left/right movement of the volume hand (for example) controls the mix of the two oscillators (for example.. fully left giving osc 1 output only, fully right giving osc 2 output only, centre giving equal mix of both, up/down giving control of overall volume as per normal)
This is, I think, as far as theremin polyphony can go.. anything more and one would need to take control away from the player and place it in the 'hands' of a microcontroller.. and IMO such an instrument would lose the essence of what we love about the theremin.
There is something similar in the above to what happened to the analogue synthesiser.. In the early days they were all monophonic, and when they became polyphonic they lost (IMO) the features which had made them great - I see the theremin and monophonic synth as quite similar - the player is concentrating exclusively on one sound, and getting more expression from this one sound than they could get when multiple sounds / chords are being played.
Fred.
Having multiple pitches tracking each other is possible now with present technology - simply use CV and drive several oscillators detuned from each other.
Duophony (two seperately controllable pitches) is possible and usable - one pitch determined by hand <-> antenna distance (capacitance) and the other pitch being related to this, but being offset by the hands vertical position - as in, if the hand is alligned to the centre of the pitch antenna, both oscillators produce the same pitch, raise the hand and the 2nd oscillator pitch increases with respect to the first 'master' oscillator.. lower the hand and the pitch of the 2nd drops with respect to the master oscillator.
The above also really needs seperate volume control for each oscillator - this can be achieved by adding an axis to the volume antenna - so left/right movement of the volume hand (for example) controls the mix of the two oscillators (for example.. fully left giving osc 1 output only, fully right giving osc 2 output only, centre giving equal mix of both, up/down giving control of overall volume as per normal)
This is, I think, as far as theremin polyphony can go.. anything more and one would need to take control away from the player and place it in the 'hands' of a microcontroller.. and IMO such an instrument would lose the essence of what we love about the theremin.
There is something similar in the above to what happened to the analogue synthesiser.. In the early days they were all monophonic, and when they became polyphonic they lost (IMO) the features which had made them great - I see the theremin and monophonic synth as quite similar - the player is concentrating exclusively on one sound, and getting more expression from this one sound than they could get when multiple sounds / chords are being played.
Fred.