Poor volume control range

hi folks,
i am having an issue with my theremini.
even i calibrate 1ft range between low position and high position, volume don t change much and the suddenly, when my hand reach 5cm of the plate, bim the sound reduce on 2cm range from max to null
is it normal behaviour? how can i increase that?
thxx for your time

nobody has a clue?

My guess is it's probably popped (ESD).  Did it work OK before?

The theremini has a poor, if not to say almost useless small volume field, due to the waaaays too small volume loop. Even with meticulous tuning and calibrating, it is not possible to go mor far that having it as a simple volume on/off switch. That’s one major design flaw and can not be fixed. Expressive and musical playing is just impossible on these instruments. Even the simple and cheap Etherwave Standard Theremin has (if well tuned and calibrated) a volume field which is by default 5-6” high and can be extended to about 10” when turning the volume tuning knob to 9 o’clock.

Moog Music inc should be fair and tell openly that the Theremini is not a true theremin, but a wavetable synth with a rudimentary gesture control, and that at this low price, nobody should expect getting a fully usable music instrument.

thank you to both of you for your response,
so in fact i own a toy  the only tweek i ve found is to set volume to 30% in the theremini editor, that soft the volume curve.

theremini is still lot of fun, i guess i ll have to practice the volume pedal then might be more efficient  i was just worried that i was doing something wrong in my calibration process.

Encore merci for your help, nobody plays theremin here in my area (annecy , .fr) hard to find answers to questions, hopefully i ve found this forum  
thank you for your time!

My guess is it's probably popped (ESD).  Did it work OK before?

always worked this way so far :/

nocomp, maybe try to find a working model, perhaps in a local music store, to see if it behaves like yours does? 

I had one of the early ones for a couple of weeks, but don't recall the volume field being that non-linear. 

You might also make a video of you doing the default calibration with a quick demonstration of the results and post it to YouTube with a link here.  You might also send the video link to Moog Inc. and see what they have to say about it.  It could be that you just have a bad one from the factory, though IIRC others have mentioned the pitch / volume axes getting popped - presumably via ESD as there is no ESD protection (!) on the Theremini CMOS oscillators.

And, yes, as Thierry notes, the Theremini unfortunately straddles the toy and musical instrument categories.  It's an oddly chosen (electronic effect rather than organic sounding) synth with low quality (slow response & poor linearity) C sensors tacked on.

thank you for your advices, i ll do that, and keep you posted.
one thing about the theremini, it s an easy way to step in the theremin world, and now i want an etherwave or else

The Etherwave has it's own set of issues, but at least it isn't a toy.

The Etherwave has it's own set of issues, but at least it isn't a toy.

damm you said too much now, what are the issues? i bet that none has issues
pitty there are not that many theremin manufacturer