Theremini calibration help! 2nd unit still not working.

I’m eager to learn some basic theremin to put into my music productions so I ordered a theremini last week. I got it home, set it up on a mic stand in a place free of obstructions. I ran through the calibration procedure multiple times. I turned the auto tune down because I can’t stand the sound of it and my ears are pretty good. 

However the theremini only stayed in tune while my hands were close on the highest octave. As I move them back the pitch quickly wavers between semitones. I tried using the ground wire - tied it to a radiator, held it, patched the output into other gear. No luck the pitch does not hold steady. 

I called zzounds where I ordered it from thinking it was defective I ordered another. Same exact issue. I spent an hour last night Troubleshooting it - changing the octave range etc.   help!!!! Can it really be this difficult to set up for stable pitch ? Would I have the same issues with an ether wave?

"I’m eager to learn some basic theremin to put into my music productions so I ordered a theremini last week." - speedo

Ah, I think I see the problem ;-)

The Theremini has exceedingly weak electrostatic fields, like a couple of volts swing at the antenna, so literally anything can interfere with it.  Try it at a different location entirely, preferable somewhere on ground level.

It might also be that you are not calibrating it correctly, the manual is vague here, the process itself fairly opaque.  I kept mine long enough to crack it open and read the entrails, then promptly ditched it on the used market.  It's a fantastic toy / conversation piece, and that's about it.

Maybe try an Open.Theremin, or try to find a used Etherwave that hasn't been monkeyed with.  You might still be able to order a Claravox, but they seem plagued with various issues.

Thanks. So it’s not me? 

I just budgeted out an etherwave. We’ll see. 

The open theremin looks like a great project. How does the sound compare? Any idea when they will be back in stock?

I fail to understand how a company like Moog can so widely distribute a product like this? They are so reputable and make great products.  Is it perhaps because I’m on a 3rd floor in a major city? Is there just too much interference? Will it be the same with a “better” theremin?

Maybe these tutorials can help?

"The open theremin looks like a great project. How does the sound compare? Any idea when they will be back in stock?" - speedo

I've never seen one in the flesh, but just about every Thereminist seems to own one and like it.  Looking at the schematic, I believe it has weak fields like the Theremini.  The MIDI code is good!  The processor is rather underpowered though.

"I fail to understand how a company like Moog can so widely distribute a product like this? They are so reputable and make great products."

The Theremini seems designed for the geeky nerd market, rather than the serious musician market.  But they market it towards the latter too.  Their main Theremin designer has unfortunately passed on.

"Is it perhaps because I’m on a 3rd floor in a major city? Is there just too much interference? Will it be the same with a “better” theremin?"

Theremins have to sense femto-Farad changes at some distance with sufficient stability and in real-time, so they're always kind of an accident waiting to happen.  Some are better at rejecting RF and mains hum than others, and much of this is accomplished by having higher voltages at the antennas, which tends to swamp interference.  The Etherwave is a higher voltage design.

Oddly enough my own Theremini has (similar?) a problem too now. I hadn't played it for a few months, when it was still working as it should, and after hooking it up in a setup that had worked before (theremini connected to a Behringer tube pre-amp into Vox Pathfinder amp, connected to a grounded outlet) this evening, after going through the calibration, where I noticed that my low note was unsteady/wavering while doing the volume. After the calibration I get a small range close to the antenna then getting further from the pitch antenna the tone keeps stuck on a B5 (with the classic theremin preset) for about 15-20 cm then it starts responding buth with a wavery unstable tone. Tried another 12V power adapter, connected the theremini line out directly to the amplifier, went through the calibration multiple times, took out and reinserted the pitch rod, but that all didn't change anything.

Yep. That’s it exactly. Mine won’t go past a certain point and anything further than 8” radius from the antennae is unstable. 

I'll be doing some more testing in different locations in my house, but it has become quite unplayable as it appears now. It is still under the 3-year warranty from the shop I got it from, so (probably best to wait until after the busy festive season) I'll be sending it in for repair under warranty and see what comes out of that.

The Theremini was the second thermin I bought (everyone has to have more than one theremin - LOL) and I’ve never liked it - it’s sluggish and, in my opinion, is a fun toy to mess around with. As it didn’t take long to realize that the Theremini is not a serious instrument, I started looking around for something else while in waited for my Claravox. During some of that time, i got an Open Theremin and, for the price, is a great little instrument; it lacks the bells and whistles of the Theremini but who cares if you’re looking to learn the instrument.

I then (very gratefully found dewster’s D-Lev and, without question, it’s my favorite instrument. While I know have my CVox (I received that three months ago, although I finally just received the stand a couple of days ago), I believe that the D-Lev is the superior instrument. 

Regarding calibration, the Theremini is a bit complex to setup and calibrate, the Open Theremin (both V3 and V4) are simple, the CVox is very unintuitive and challenging, and the D-Lev is initially quite complex to initially setup (after that, it’s easy) and once done, calibration is very easy.

Hm, I miscalculated and my Theremini isn't under waranty anymore. With some more observations I noticed that in the range lower than the range where the note gets stuck, there is an interference/modulation going on, like there is a constant tone that mixes with the variable tone.