Theremini Pitch Calibration Problem

Posted: 9/20/2019 10:46:29 AM
EmmaNZ

From: Wellington, New Zealand

Joined: 9/20/2019

Hello All,

I've just recently acquired a Moog Theremini, and I'm trying to navigate my way around calibration and setting everything up. I know the Theremini is often met with sighs of contempt, but I'm really enjoying it so far!

However, I am having problems with calibrating the pitch antenna. I've seen this issue raised so many times, both on here and the Moog support forum, but I can't find any responses for my problem. I understand how to do the calibration process, and how to set the pitch range of the instrument. I've currently got it set on a 4 octave range. The unit itself is set up on a microphone stand, as per recommendations, so no chance of interference from hidden metal in a table or anything.

When I do the calibration process, I can't seem to find zero beat. The theremin will say that it's calibrated for 4 octaves (according to the settings), but it won't play the whole range, I'll only get maybe 2 octaves from my chest to the pitch antenna. The rest seem to be several feet behind me, and I can't find the lowest range/zero beat at all. If I step far away from the unit, it will continue to make sound, even though I have the 'automute' function on the pitch antenna turned on. This happens when the pitch correction knob is on 0%.

In the above scenario, when I turn the pitch correction knob to 100%, suddenly I have the opposite problem. The pitch field gets incredibly condensed, it will now play all 4 octaves in the space of a foot. Zero beat will be halfway between the pitch antenna and my chest. My understanding is that the pitch correction knob isn't supposed to alter the size of the pitch field, as it does in my situation. Can someone verify that this is correct?

I've tried calibrating my Theremini in different environments, plugged it in to different wall sockets. I can never get it to calibrate the same way twice, even if literally nothing in the room/environment has changed. Because the pitch field is widely variable every single time I use it, even with the same settings and calibrating it the exact same way, I can't go on to focus on my technique because there's no stability whatsoever. It really is a lucky dip as to what the pitch field will be like, and how many octaves I get to play with (regardless of what settings I choose).

I don't mind having to frequently calibrate it, and I understand it's highly sensitive to it's environment because of it's very nature. I just don't understand why I can't correctly define the pitch field as per the calibration instructions?

I was thinking a factory reset would be the first place to start. I can't seem to find any instructions on this anywhere, could someone please assist?

Many thanks in advance for your help!

Posted: 9/20/2019 3:08:15 PM
DreadVox

From: The East of Netherlands

Joined: 6/18/2019

Welcome to the Theremi World forums Emma,

reading your questions I'm wondering about a few things, are you actually doing to the callibration procedure (stepping away 1 1/2 meter, close and far from pitch antenna (the hand far from pithc antenna position should set the zero beat distance) and close and far from volume loop, because how many octaves you set is not part of the callibration procedure, but a setting which is (only) available while the theremini is set in 'theremin mode' (in Advaced section of the Setup menu).
The other question that arises is if the theremini has a proper ground/earth connection (either through the power adapter, by being connected to an amplifier that has a safety earth/ground connection, or via the GND screw on the back. Without being properly grounded one would encounter the kind of situation where properly callibrating is not possible. When the thereminiis in theremin mode (which is somewhat buggy and Moog should fix the firmware) the pitch correction dial and the effects dial do not work as such, but are the tuning dials for the pitch and volume fields, as the display shows.

Last year I started off with a theremini and had lots of fun and playing and learning with it and even played in a few jamsessions with it before buying an Etherwave theremin, as I started to bump into the limitations and had determined that I needed a more precise and sensitive all analog theremin to progress further in the directions I found out I'm going. I must admit that I didn't play the theremini very much anymore after getting the Etherwave, which is much smoother and precise to play, but I think for some purposes, like for example a pure sine bass tone, I'll sometimes will be using the theremini for recordings/loops.
Perhaps at some point I'll add an Etherwave standard with an ESPE01 module to my arsenal, but I'm kind of thinking to myself that I'll do that once I have earned the money needed for that doing some gigs.  Now doing jams and what are still somewhat (unpayed) try-out gigs to let the forms it will take crystalize out some more. I'm kind of dreaming and hoping that I might be able to do for the theremin what I did for the yidaki/didjeridu in the 80s/90s, helping to bring it out of its current obscurity again, and inspire more people to start playing and help it unfold its many as yet unrealised potentials.

Aiming to be 'ready to roll' for 2020, presumably the 100th birthyear of the theremin, although different sources come up with different years and the whole history of the instrument is somewhat nebulous. Early experiments/experiences while Leon Theremin was still in the army may have been the roots of the instrument, probably something which was an error condition in the first regenerative radio recievers (The Mexican Dog howling sounds that would occur when the feedback was set too high and the radio receiver would begin to self-oscillate). Leon Theremin may also have picked up some ideas from the Audion Piano concept by Lee De Forest, inventor of the triode tube in 1915, which, as it seems never got fully realised, but was the first concept of a musical instrument using heterodyning as a tone generating principle. More about the Audion Piano on this link.
I does seem certain that the theremin was demonstrated to Lenin in 1920, so it is likely it at least got its definitive form in that year.

I hope you will get your theremini set up and callibrated properly soon and can start practicing and playing.


Posted: 9/20/2019 4:58:06 PM
rupertchappelle

From: earth

Joined: 5/8/2017

Do you have a music instrument cable connected to the theremini which is plugged into an amplifier? If so, make sure it is long enough to lay a considerable portion of the cable on the floor. That should provide proper grounding so you can adjust the pitch field properly.

The symptoms you describe sound like you are using a headphone to listen to the theremini rather than an external amplifier and thus without proper grounding of the instrument cable.

Adjusting the pitch field would be easy unless there is a component failure or the internal adjustments have been messed with - which will prove trying if they need to be recalibrated.

I don't have a Moog theremini, but this is a common problem with new players. It isn't like a synthesizer.

Posted: 9/20/2019 6:35:24 PM
DreadVox

From: The East of Netherlands

Joined: 6/18/2019

Actually, with the Moog Theremini, when connected to a power socket with safety ground the (rather cheap crappy made and prone to introduce a weird soft but annoying warble noise into the theremini sound output) power adapter is providing grounding.

Personally I do advise, against what Moog writes in the manual, to get a regular third party 12V power adapter (make sure it has the right tip polarity and minimum mA power specifications) like one for Yamaha keyboards, and play the theremini through an instrument amplifier that is properly grounded through the power grid's safety earth. Using a long instrument cable to get a capacitive connection to earth when there is no safety ground to connect to available can be an alternative solution that should work good enough to callibrate and set up the theremini into a playable state.

Posted: 9/23/2019 4:06:59 PM
rupertchappelle

From: earth

Joined: 5/8/2017

I never trust power from the wall socket to be grounded, I am that old.

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