Totally failed experiment...lesson learned?

Many thanks to all for the illuminating replies. Perhaps I am being unwarrantedly pessimistic, but at 2 meters in height and 135 kg in weight, I think I'm going to leave some footprints on the rice paper. While my hands are moderately nimble, they are also roughly the size of your average canned ham. Electromagnetic fields, beware!

Pod
2XLT resistive field/capacitance plate

RS Theremin wrote:

"The energy of the heterodyne theremin focuses in on the least resistant point which would be your forward finger tip with very little influence of anything behind it at that specific location in the pitch field."

carport888 wrote:

"The Theremin fields are affected by anything with capacitance, but the object with the most capacitance closest to the antennae will affect them the most, whether it be your guitar or your closest finger."

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Both of these somewhat agreeable comments are correct...to a point. I cannot argue the technicalities of theremin design or antenna radiation, so I will stick to the observation of cause and effect.

The electric field around the theremin antenna is affected by almost any material depending on its physical properties and depending on its size and density (mass). Metallic and water-containing materials (such as flesh and even living plants) seem to have the greatest effect.

On your guitar, the wooden neck would have little effect. However, the metal tuning heads, the metal strings, and the metal bridge at the other end which are all connected will act as one object. The individual metal frets will also affect the field as well.

When you touch the strings with your hands, you add your body to the mass of the "circuit". (So to speak.)

Assuming the tuning heads are closest to the pitch antenna, they will determine the starting pitch, depending on how the tuning knob has been adjusted.

Even so, any movement of any part of that chain of objects, or any other separate objects in the field, will then affect the pitch.

I believe that electric fields are more concentrated on the edges and points of objects; therefore it is (thankfully) possible to affect the pitch field adequately with your fingers/knuckle extensions even though they may be close to the much larger mass of your body. (And, for some of us, a prominent belly.)

The utility of it is this:
Some lower cost theremins have a significantly non-linear pitch field with the pitch rising ever faster as you approach the antenna. To a point, all theremins have a compressed pitch range when you get very close to the antenna.

Normally, it is not a problem to play over most of the range using knuckle or finger extensions until you approach the antenna when the movements required are increasingly tiny.

At this point, moving your whole body closer to the antenna raises the pitch, just as your hand would. But, it also has the effect of stretching the remaining pitch range out making it far more playable with finger/knuckle extensions.

The experiment video is up at

http://www.youtube.com/watch?v=TU3pgLYdjhQ&feature=email

I don't know if this experiment will contribue anything worth while to this discussion, but it's interesting none the less.

Enjoy.

I love the fact that Mr. Grillo even did the experiment, no less filmed it. I didn't have the cojones to film my experiment, or even to allow family members to witness it.

I'm glad he has the performance gene.

Pod

I don't understand the science behind the fields surrounding the rod and loop, and I have read various different explanations from theremin builders. But, from a playing point of view it is perhaps not so important to have a scientific model of the fields as it is to have a musical model. One acquired through experience and exploration, rather than deduced from theory. Knowing the equation of a parabola never helped anyone learn to catch a ball.

So there is a point to playing games with the fields, exploring and experimenting; it's all about getting a feel for them - developing ear to hand/arm/body coordination just as one learns to balance on a bicycle by developing the appropriate coordination. Or perhaps a better metaphor would be learning to use a pencil - both involve using fine motor control to communicate feelings and ideas, the one by writing or drawing, the other by making music.

And fine motor control brings us to the ham-fisted thereminist, as you characterise yourself, Pod, although I have no reason to suspect that this would imply ham-fistedness in a pejorative sense. However it is interesting to note that there [i]may[/i] be a relationship between the stature and hand-size of a player and the appropriateness of different playing techniques.

For instance, Pamelia Kurstin is slight of stature with small hands, and uses the pitch method developed by Clara Rockmore, also a petite person. And both Carolina Eyck and Charlie Draper are slim, with long thin fingers, and both successfully use the Eyck method.

Hey Podmo, I was going through some studio footage yesterday, and it dawned on me that without realizing it, I'd unintentionally duplicated your "failed experiment", only this time, there was another musician in the studio at the time. He was playing guitar, and in the worst possible postion for a thereminist. The peg-box of his guitar was within just a few inches of the pitch rod, and I noticed that (as you mentioned) as his hands moved along the fretboard, there was no change in pitch, until his guitar moved, or I moved my hand. It's all captured here in this vid.
http://www.youtube.com/watch?v=Um_omSsanzE

We later corrected the positional problem.