I notice a new (or at least ive never seen it before ;-) theremin has found its way into our photo albums, from a new member assec. Welcome assec!
Hey! That horizontal volume antenna was an idea I floated here a while back, but was rejected by everyone here! - Everyone wanted their precious loop! - I should have just bloody ignored them! :-)
Anyway, it looks real compact and neat to me - that pad under the 'control box' - is that metal to extend the ground field?
Interesting theres such a long lead to the antennas - Are these active antennas (as in, is the oscillator actually built into them?) - I presume they must be.. I suspect the VFO is in the pitch antenna, and the reference oscillator is in the box ... And that the volume antenna is self-contained (all circuitry is in it, except perhaps the VCA)
I do like the look of that antenna arrangement! Really stable.. Have been thinking on the same lines, but having the box on the floor makes it a lot simpler!
Fred.
OH! - Correction.... Thats not a grounding pad - its a "volume sensor" .... Now this is really getting interesting! I can think of one TW member who may well be even more interested than I am! ;-)
A few questions jump to mind..
Looks like there is only one knob on the control box - Tuning... [Edit] -> So how does one tune the volume sensor pad? (I notice a tuning control on the optional volume antenna). Ok.. I see that its not a capacitive foot sensor, its a pressure pad.
Two audio waveforms out on separate connectors - One "harsh" and one "mellow" - Is there a separate VCA on each? Is there any way to mix these to taste other than with an external mixer?
Been listening to the samples.. Well, some sound closer to playing a tune than I have heard from the Theremini ;-)...
The "harsh" sample isnt that "harsh" IMO - Quite usable, and reasonably clean. IMO theres no point in any of the other samples (other than to demonstrate that perhaps one might actually manage to play the thing) as they sound horrible, and give loads of ghost tones and rubbish... This leads me to think that lots of HF might be coming out on the audio.
There is something that looks like it might be a preview output (Nano "Pitch Spy") but this is unclear to me - A picture of the connectors would help.
The core "harsh" waveform (at about A2) is this:
and its rich in odd and even harmonics.. The harmonics (core waveform) doesn't appear to change as frequency is swept, except that there is obviously a simple LPF rolling off the higher harmonics - I recon there's a 1st order filter (RC) with its -3db just under 300Hz, but that this filter probably doesn't continue this attenuation up much beyond audio, as is the way with HF.. If the noises I heard on the other samples are due to HF leakage.
There really isnt any point in doing a demo of a theremin through a TM or mush of reverb or whatever - A clean sample of the "mellow" sound would have been much more useful.. You are trying to sell the theremin, not the effects unit! - The usual reason people apply effects is because they dont want to expose their instruments sound to scrutiny.. But to me, the only sound in your set of samples that was worth listening to (and not painfully horrible! ;-) was the "clean" one.
ADDED ->
More concerned about the samples after listening again.. I think that perhaps (just perhaps) the horrible tones on the "soft" sample could be from volume interaction - The clean "harsh" sample is, I think, the only one where volume is not being modulated by the volume antenna.. The "noises" are on the "soft" sample.. Some artifacts are present on the other samples, but you cannot hear the theremin on these as its driving things that are extracting pitch data and the mix is 100% wet, so its impossible to say whats happening.
They may not be related - all the tones and distortions may be coming from the effects units.. But if they are coming from volume oscillator interaction then its a killer.
Could we hear some samples direct from the audio outputs, when the volume antenna is being used? Because if there is a problem in this area, the cost of returns you will receive could kill your venture before its a toddler.