Fixing Claravox volume antenna

Hi,

I remember reading somewhere that you (Thierry) had a fix in the works for the Claravox's pitch antenna, both for squeaks and non-silence when touching. Is this true, and would it be possible to send you my theremin for adjustments? I trust you more than I trust Moog, even if it means I'm paying you and voiding my warranty.

I play a left-handed Claravox, and I only use my theremin in traditional mode.

Julien

Same problem with my Etherwave standard (squeaks when touching volume antenna).

I'd recommend some sort of insulator, at least over the area where you tend to touch the loop.  I've seen others do this with their units and it doesn't otherwise affect the response.  It's good protection for both ESD protection and undesired behavior (in a perfect world all Theremin antennas would be fully insulated IMO).  They make very thin & clear heat shrink tubing that would probably work and not impact the looks much, though the thicker the insulation the better.

Nylon sleeve. You can get it real cheap from an electronics store, doesn’t affect capacitance at all

A volume antenna which squeaks when touched is (with Moog’s principle of operation and circuits in the Etherwave Standard and Plus) perfectly normal. Even more: The better the sensitivity of the volume circuit is adjusted, the more it squeaks. 

Just don’t touch the damn thing! You should be aware of the fact that the Theremin is known as an instrument which you play without touching it… 

Shrink tube insulation does prevent this without affecting the volume response, that’s true. But it’s ugly! Better train your left hand to be less clumsy, so that you manage to mute your instrument without touching the loop.

And when I’ll have the fix for the Claravox’s problem with its insufficient dynamic range which makes that you can’t completely mute it, it risks to squeak even more when touched. As I said above, learn to not to touch the thing!

Other than the (crazy, IMO) traditional bare metal antennas, much of the problem here is caused by the (crazy, IMO) traditional volume sense, where closer = quieter.  0dB or the loudest point is a very well defined thing, whereas the silence “point” is actually an indistinct region – is it -36dB?  -48dB?  -64dB?  Of course it depends.  With traditional sense this region is placed in the near-field, so if you need more silence you may end up hitting the antenna, and indeed this is probably why it is a loop.  Reversed sense places 0dB in the near-field, so there is no need need to get any closer when playing – and if you need more silence you just move your hand farther away.

Other than the (crazy, IMO) traditional bare metal antennas, much of the problem here is caused by the (crazy, IMO) traditional volume sense, where closer = quieter.  0dB or the loudest point is a very well defined thing, whereas the silence “point” is actually an indistinct region – is it -36dB?  -48dB?  -64dB?  Of course it depends.  With traditional sense this region is placed in the near-field, so if you need more silence you may end up hitting the antenna, and indeed this is probably why it is a loop.  Reversed sense places 0dB in the near-field, so there is no need need to get any closer when playing – and if you need more silence you just move your hand farther away.

That‘s the respectable view of an engineer, but probably not the one of a musician who probably associates huge movements with increased volume and musical expression while returning to a default position is associated to silence.

BTW: Me thinks that the volume antennas have traditionally a loop form to „bundle“ the field, being much more sensitive vertically = above (and below) and less horizontally since the player‘s body is most times closer to the volume loop than to the pitch antenna. And an unwanted hip or paunch mute is not appreciated.

BTW2: 52dB is not enough as we have seen on unmodified Etherwave Pro because the step from silence to -52dB was clearly perceptible. With the EPVM1345 module, the range is extended to around 74dB which is considered acceptable by professional EPro players like Carolina Eyck or Thorwald Jorgensen.

Shrink tube insulation does prevent this without affecting the volume response, that’s true. But it’s ugly!

Fortunately I myself am handsome enough to compensate

And when I’ll have the fix for the Claravox’s problem with its insufficient dynamic range which makes that you can’t completely mute it, it risks to squeak even more when touched.

 Can’t wait to see what you come up with!

"That‘s the respectable view of an engineer, but probably not the one of a musician who probably associates huge movements with increased volume and musical expression while returning to a default position is associated to silence."  - Thierry

This is my view as a lay Thereminist.  And with my instrument set to closer = louder my resting position is also silence.  IMO if large volume hand movements are necessary then the instrument itself isn't very good.  There is a happy medium to be found between flapping like a bird and too tight.

"52dB is not enough as we have seen on unmodified Etherwave Pro because the step from silence to -52dB was clearly perceptible. With the EPVM1345 module, the range is extended to around 74dB which is considered acceptable by professional EPro players like Carolina Eyck or Thorwald Jorgensen."

Yes, the D-Lev digitally ships out 24 bits to the DAC, which could in theory give -144dB of silence, but limiting factor here of course is the analog noise floor of the DAC itself.  The 32 bit internal dynamic headroom is actually necessary since the filters can have gigantic gain when set to very high Q.

  You should be aware of the fact that the Theremin is known as an instrument which you play without touching it… Shrink tube insulation does prevent this without affecting the volume response, that’s true. But it’s ugly! Better train your left hand to be less clumsy, so that you manage to mute your instrument without touching the loop. As I said above, learn to not to touch the thing!

It may not be my place to say anything because Bendra can certainly speak for himself but I think he should be able to wrap the antenna with white surgical tape and bubble gum if he wants to without being chastised.  Maybe something is lost in translation but to me these comments come across as mean spirited and tactless. Thomas Grillo used woven cloth insulation on his volume antenna. He may have done this because of his vision disability. Would you tell him he doesn't need to insulate the antenna because he is clumsy?