"The Moog SERIES 91 theremins are all VC synthesizers. Does that mean they aren't really theremins at all?"
Hi Peter,
You know that in the past I have been a pedantic A*hole ;-) - well, ive mellowed a bit! I dont like the fact, but it is a fact - the word "theremin" is generally used for anything where pitch is changed as a function of proximity.. And I have decided that there is no point in trying to be a one-person 'barrier' against the acceptance of this "definition".
Its a bit like the question as to whether a theremin is a synthesiser - I believe that it falls within this classification, you (and apparently Bob Moog shared this view) believe it is not a synthesiser.. So be it!
There are a group of specifications related to what "should" "could" and "is" called a theremin today - there may be more which I miss, but these are off the top of my head:
1 – Proximity sensing:
1a: Pitch controlled by proximity sensing
1b: Pitch controlled by capacitive proximity sensing
1c: Volume controlled by proximity sensing
1d: Volume controlled by capacitive proximity sensing
2 – Real-time Control other than by proximity:
2a: Control of pitch
2b: Control of volume
3 – Method of operation / sound generation:
3a: Analogue variable oscillator VFO directly connected to pitch antenna, sound generated by analogue heterodyning with REF oscillator. [Moog EW etc, my H1, EPE, SC etc]
3b: Logic level mixed signal VFO, or VFO directly connected to pitch antenna, converted to logic level, followed by mixed signal processing / heterodyning [Moog E-Pro, and some of my prototypes and my H1]
3c: Conversion of pitch antenna proximity to a quantization free voltage, and from this voltage driving a non-heterodyning sound engine (synthesizer). [Moog 91 series + my FDL P/T]
3d: Conversion of pitch antenna proximity to a quantization free voltage, and from this voltage driving a heterodyning sound engine. [FDL P/T only]
3e: Conversion of pitch antenna proximity to a quantized numeric (digital) value, and from this value driving sound engine. [Dewsters Digital Theremin P/T]
It is my view that only instruments complying with 1a qualify for possible inclusion in the theremin ‘family’ – that instruments where pitch ‘data’ is derived from any other method (such as resistance) do not qualify.. Forks which make noises using the conductive path from the hand, via food, to the mouth, for example, do not qualify! ;-)
My ‘pedantic’ self would declare that 1b and 1d are required for a “true” theremin – but I am not my pedantic self anymore!
Any instrument where 2a applies is, IMO, not a theremin.
I feel that all methods of operation / sound generation in 3 are “acceptable” – but that (being pedantic again) 3e is only acceptable if quantization is below perception.
And to answer your question:
The moog 91 series are not just VC synthesizers, they fall in my category 3c (catagory 3d does not, to my knowledge, exist in the market yet - I have, I think, the only prototype of such an instrument), and are therefore theremins – as is the E-Vox.. When used as a theremin, they are theremins, when driven from an external controller (2a and 2b) they are not being used as theremins – if this is how one always used them, one could chop off the antennas, and they would no longer be theremins, they would be crude synthesizers!
Likewise, if one had an instrument which put out voltage or MIDI signals (as a result of proximity) but did not produce sound, I do not believe this would be a theremin – Only when connected to a sound engine (synthesizer) would the system become a theremin – neither part on its own would be a theremin.
I have chosen to make proximity sensing the primary criterion on which to qualify instruments as "theremin" or "non theremin" - If one chose to make heterodyning the primary criterion, then the 91 series would not be in the theremin family. but the odes martenot would be a theremin.
If one was to declare that only instruments conforming absolutely to the design principles given by Lev Termen, this would be 1b, 1d, and 3a - the 91 series and E-Pro (and many other) theremins would not qualify.. If one was restricted to the same (tube) construction, there would be very few theremins in the world! ;-)
Fred