Moog Music Forum

Harald now got also a new Theremin and we plan to do a session with two Theremins. Does anybody has recommendations for that? What would be a good distance between to avoid interferences?
Any tip is very welcome.

All the best:

Niko

The needed distance in order to avoid interference depends on the theremins. Some models have a stronger radiation field (i.e. the tVox tour on the volume side) than others. If you need to set up two identical models (i.e. Moog Etherwave standard) together, it's still more difficult since you'll have 2 + 2 = 4 pitch oscillators working at about 288kHz which may interfere and 1 + 1 = 2 volume oscillators working (and interfering) at about 510kHz.

When doing theremin ensemble setups during festivals I saw that 2 Etherwaves can coexist with almost no interference at a distance of 4 to 5 meters if they are plugged on separate amps each (self-understanding that each player's equipment is respectively plugged to wall plugs at opposite walls of the room). I said "almost no interference" because out of the "through the air" problems there will remain some stray RF migrating through the power supplies so that the timbres in the lowest register risk to become somewhat harsher.

Best would be to use two theremins with different oscillator frequencies AND somewhat different construction principles. At home in my workshop a Moog Etherwave Standard (288kHz and 510kHz) and a Paia Theremax (800kHz and 900kHz with much less oscillator voltage at the antennae) coexist and co-operate without problems.

Hi Thierry,

many thanks for your reply. It seems to be that quite a lot of technical issues needs to be concerned, even the wall plug supply. Well, it makes this instrument even more interesting to me. And we will see whats going on during the planned session. Which will be held in my little studio with limited space. We have two standard Etherwave Theremins and one Etherwave plus which I would like to hook onto the Voyager. So in fact in total 3 Theremins will stuff my little room (20square metres) with interferencies. I'll keep you updated herewith.
Thanks again and

best regards:

Niko

just an update. We've had now our first Theremin duo session. As expected quite stressful so far as the arms and shoulder movements were concerned. Because the Theremin always produces sounds if the player stands close to it (and not touching or approaching closely the curved left antenna) we played more than one hour continously and moved our extremities and sometimes excercised even head banging movements towards the upright scale antenna. Now I have nice aching muscles and a nice SD card full with strange and never repeatable etherwave vibrations. In fact one of the most difficult issue is actually to keep a certain tone to a constant frequency I think.
Interesting also was to stand between two Theremins and played these two instruments simultaniously by one player. A duophonic set up was achieved which worked very well. For the next time we'll consider to use a stereo volume pedal to achieve the dynamic control as well (unfortunately I only had two arms on my body which I used both for the upright scale antennas). Or maybe I should lay down on a couch and control the volume antennas by my legs (?).
Anyway it was a great pleasure and a lot of fun. And a related video will follow soon (will be published by Harald soon). And here now two fotos as a teaser already:

Niko wrote:Interesting also was to stand between two Theremins and played these two instruments simultaniously by one player. A duophonic set up was achieved which worked very well. For the next time we'll consider to use a stereo volume pedal to achieve the dynamic control as well (unfortunately I only had two arms on my body which I used both for the upright scale antennas). Or maybe I should lay down on a couch and control the volume antennas by my legs (?)

When I tried that a while ago I arranged the theremins in a V formation - with the volume loops close together so I could control them with my hips, whilst reaching out along the length of the theremins to control the pitch rods with my hands. Each theremin was fed into a delay pedal - with a different but related delay on each (one was twice as fast as the other, or something like that) and once I had got the tempo into my head playing them turned into a funny little dance.

There were some interesting modulations and interactions from having the two etherwaves so close to one another. It made them very unpredictable, but lots of fun!

Thierry wrote:When doing theremin ensemble setups during festivals I saw that 2 Etherwaves can coexist with almost no interference at a distance of 4 to 5 meters if they are plugged on separate amps each (self-understanding that each player's equipment is respectively plugged to wall plugs at opposite walls of the room). I said "almost no interference" because out of the "through the air" problems there will remain some stray RF migrating through the power supplies so that the timbres in the lowest register risk to become somewhat harsher.

Thierry, is there a practical way to reduce the amount of RF migrating through the power supplies? I am thinking about using long extension cables, for instance, when it is not possible to use wall sockets on opposite sides of the room. (If this would help, would it matter if the extension cable were coiled or uncoiled.)

I have read of an instance where the earth lead of an extension cable was disconnected from the plug at the end of an extension cable furthest from the theremin to reduce interaction between theremins in a large installation, while still providing sufficient grounding for the theremin to function correctly. (I should point out that the person doing the disconnecting was the designer of the theremin in question - not a Moog Etherwave - and he knew that for his theremin this was a safe thing to do. Naturally this is not something I would do without being certain that by doing so I was not increasing the risk of electrocuting anyone in the event of a circuit failure.)

Hi Gordon,

good point to arrange two Theremins in a V-configuration. This means that only one of it allows access to the control knobs but this may acceptable during the performance. Are the two Theremins on the same hight level or the two volume antennas were in a kind of a scissors configuration one upon the other?

I arranged the theremins at the same height, with 30cm separation between the loops, so that I could more my hips forwards and backwards to control the overall volume of both theremins, and from left to right to alter the relative volume between them.

If you put the loops too close to one another each one will mute the other theremin.