"The particular quality of the heterodyning analog theremin instrument is unseen as it is the ability to express deep fluid emotion while a modern synthesizer will just sound pretty." -RST
Chris,
I believe I understand the source of your rather beautiful "the ability to express deep fluid emotion" - but I am not sure that it is only "the heterodyning analog theremin" which is capable of this..
It is my opinion that any instrument, in the hands of a gifted musician, is capable of expressing their "deep fluid emotion"- But some are better suited than others.. Sax, analogue synth, electric guitar, theremin - these 'lead' instruments particularly come to my mind as instruments with great 'emotive' expressive capabilities.
I think perhaps that the theremin is 'best' (in the hands of a skilled thereminist) because it is less restrictive than the other instruments - both pitch and volume are absolutely under the performers controll, there is no natural decay to the amplitude, no defined vibrato speed or depth, no preset portamento time - everything is absolutely under the performers control.
In particular, I think it is the control of pitch / vibrato which gives the theremin the edge for vocal 'simulation' - One can control vibrato with a wheel or joystick or other controller, but the theremin allows a cycle-by-cycle control of all aspects - depth, shape,speed - and it is therefore possible to do what the voice can do.
I do not think any other instrument provides such an interface - but many other instruments come close - and IMO there are only a few performers who do the theremin justice - most of us would probably produce better, more emotive music, if we went to an easier instrument!
To me, it is the interface which makes a theremin a theremin.
Fred.