Theremin problem with pitch

I have an Etherwave and have been playing for about a year. Recently, when playing it, I suddenly got about 4 octaves from it, but today, after bringing it out to a school to demo it to some high school students, I can only get about 2 octaves of notes!
My "pitch" know is usually set fully clock-wise (5 o'clock setting), so I don't see why the octave can "shrink" in this way! :-(

Anyone reading this can give me your opinion on why this could happen?
Thank you!

Khew

Other than an object in your control zone, the other issue may be grounding.

If the pitch jumps when you touch a metal part of your Theremin, particularly one of the 1/4" jacks, then you can suspect a grounding issue.

I carry with me a conductive wrist strap and a wire lead that I can clip to a ground point on the Theremin when needed. This allows me to use my body as a ground when no other ground is available.

You might want to try this -- Radio shack sells the wrist strap, etc for around $10.

How about when you touch the Pitch anteanna and it "squeals"?
Thanks!

Khew

To clarify -- in the above post I was referring to a metal part of your Theremin that is a ground point (such as the exposed metal on your 1/4" jacks).

Since the antennas are not ground points, they don't apply to the "ground" issue. Touching the antennas will produce various results depending on the make of Theremin.

HI:

It's perfectly normal for the pitch antenna to squeal when touched. Surprisingly, you can get very interesting effects doing just that.

(If a volume antenna squeals when touched - big problem.)

However, your issues of severely impaired range of octaves CAN be dealt with. It would be helpful to know a few things:

First, are you saying that once the change occurred, that your range shrank even AFTER you'd left the school -- in other words, the anomaly became permanent?

Secondly, if you are setting your pitch knob at 5 o'clock to get "zero beat", that's what I'd consider to be too far over. Is that the case -- that 5o'clock is where you achieve zero beat?

Third, has anything like this happened before?

Fourth, did ANYTHING, regardless of how inconsequential, happen to the theremin during transport? Was it unprotected (i.e., not in a carrying case), did it get jostled, knocked during setup, etc.

The most likely fix would involve re-tuning your pitch circuit – I’ve done this approximately three times to my theremin in the past eight years. It will give you back a wide pitch range again. In addition, you can also recalibrate ( perhaps not the correct term, but Kevin K. really knows his stuff and he can definitely help with precisely what to call things ) the pitch knob. In either case, you will be making very “fine tune” adjustments to the little “screws” on the tops of both the fixed and variable frequency oscillators. (How’m I doing, Kevin? ) It’s weird – I can DO it, I just have trouble SAYING it.

Both of these procedures involves opening up your theremin to make adjustments with a little plastic tool that’s like screwdriver. Exactly what to do depends upon what theremin you have. For a standard Etherwave, it can take about forty-five minutes. Increasing the pitch range is fairly straightforward. The trickiest part is getting the pitch knob to give you zero beat when positioned at about 12:00 rather than 5:00. It’s tricky because the lid has to be taken on and off repeatedly to make the adjustment.

If you’ve got a standard Etherwave, there are instructions in the manual, but they were written by Moogian Martians, so they’re a little difficult to understand.

Anyone who wants to jump in here, if you’ve performed the procedure and can offer a concise written description of how to do it?

Hi!

The only thing I'd add to Kip's excellent troubleshooting list is that I prefer to adjust the variable oscillator's coil and leave the fixed coil alone -- at least at first.

I am only speaking from my experience with the Tmax and I am unfamiliar with the Etherwave Standard's internals.

Keep us posted!

Thanks for your help, everyone!
Really appreciate the comradarie amongst Thereminists. :-)
I tried moving my Etherwave to another place in my living room where there's "more space" and voila! I get my 4 octaves again!
Before that, I was playing the Theremin between my dining table and a wall, so it was kinda narrow. But it still baffles me as to why a wooden dining table and a concrete wall would affect the pitch range of a Theremin?!! Nothing metallic here! Am I wrong in this logic?! :-o

As for the 12 o'clock setting of my pitch knob, I'm still not able to get that kind of setting as putting it at the 12o'clock setting only gives me this very high pitch octave where I have to move about 6inches to get from one diatonic note to another!
I'm only able to get the "normal" hand pitch movement of playing a melody when this pitch knob is set to maximum (the 5o'clock position)!
What gives?! :-o
Thanks!

Khew

Great question!

Anything that has capacitance will affect the pitch.

Wood aborbs quite a bit of moisture from the air and can throw off the pitch.

One time I set up out on my deck and my pitch kept wavering due to a nearby tree branch that was blowing in the wind!

The greater the water content, the more the effect. Aloe plants, for example, have a lot of capacitance and a high effect when near the pitch rod.

Ha,ha!! Looks like the thereminist is a "lonely" musician in that there should be NOTHING around him/her in that ft radius, eh? :-DD

Theremino

Nothing that moves to more than a minute degree. Provided everything around you is stationary, you're fine.