On June 18, 1997, my old pal Phil came up north to visit. For several weeks, we had been e-mailing each other about the upcoming theremin festival in Portland, which I erroneously thought was in Oregon and which Phil thought was in New York City. I know, of course, why I was thinking Oregon, but was puzzled at Phil's notion of New York. So, I questioned him on this issue while he visited. He said that he assumed that something as great as a theremin festival would deserve the grand cosmopolitan setting of the city which was, after all, the great Leon Theremin's U.S. home. Well, we both decided that Portland, Maine, where the festival was actually held, is probably a great place in its own right, but just too far away for us to travel. So, we settled for our own theremin consortium at my place in good ol' Rockville, Maryland. By nine o'clock on the evening of the 18th, no less than seven of we EM aficionados gathered to jam using three theremin-type instruments along with a multitude of other electronic devices, and even an electric guitar just to round out the sound.
Besides reminiscing our long friendship starting with our college years in the early '70s, Phil and I did a lot of comparing of the various instruments which included four of my own designs, his own Maestro(TM) theremin, and a commercial infrared MIDI controller called the "Dimension Beam 2.0," manufactured by Interactive Light, Inc. This compact unit was used to drive the percussive effects in an Alesis D4 drum module under the skillful control of my friend Jack. Although hardly an emulation of the classical theremin, the Dimension Beam is, none the less, a hands-off "gestural controller," which is therefore an embodiment of the theremin concept. Also present was one of my most recent theremin designs, a capacitance-operated (antennae) unit which features six independent analog controls of the first six harmonics. Until this design, all my theremin voices were either those of the classical heterodyne circuits, i.e., diode mixers, or a sine-wave oscillator. The harmonic-voice theremin provides the facility for timbre variation which ranges from a pure sine wave to any combination of the six harmonics, including some purely synthetic sounds, in which, for example, the fundamental is much lower in amplitude than the harmonics. The range of the fundamental is 55 Hertz "A" to 1760 Hertz "A," and the sixth harmonic provides 330 Hertz to 10560 Hertz. One of the more interesting sounds is obtained by adding harmonics four and five, along with a little reverb from a Korg DRV3000. The result is a truly eerie sound reminiscent of those which could be produced on the old Arp Odyssey synthesizer. Alternately, by adding the fundamental with a little of the third, electric organ sounds can be produced.
Well, about three months of strenuous design efforts had gone into the harmonic generator used in this theremin, and although it proves itself a diverse instrument, I still favor the pure-as-possible sine wave voice over the more complex harmonic additions. The sine wave sound is, of course, a very nostalgic sound for many EMs, and perhaps I favor it mostly for that reason. On the other hand, I noticed that certain harmonic combinations do come in handy to suit particular accompaniments, e.g., the organ-like sounds go well with blues guitar lead, and the more exotic combinations suit freeform improvisations. An interesting observation in comparing the sine voice with a harmonically rich voice is that the presence of harmonics, especially "unnaturally" exaggerated combinations, proves a greater challenge in keeping pitch. Again, perhaps due to familiarity, the pure sine wave seems the best ticket for playability.
In my harmonic theremin, the harmonics maintain a constant phase relation, so in some respects, the sounds, although distinct over many combinations, lack the luster of combined asynchronous oscillators. Perhaps two or more sets of harmonic variables, each asynchronous and independently tunable, would be useful in making the sound more interesting. I have, in the course of browsing the web, seen at least one version of the theremin with such multiple voicing. Of course, all the electronic embellishments conceivable can not substitute for adequate playing skills! I have decided that my next focus will be on improving the parametric qualities of the single sine-voiced instrument, including improvements in sensitivity, smoothness, and signal to noise.
In our comparisons, I also examined Phil's Maestro(TM), and noticed that the instrument's response was limited to relatively close hand positions, and that its lowest pitch was relatively high, about 300 hertz. I believe that these attributes arise from a phenomenon called "injection locking," in which the pitch circuit's variable oscillator is coupled by excessive stray capacitance to the fixed ("local") oscillator. This same condition occurred in my own heterodyne instruments, and can be diminished with proper shielding and component topology. It is this injection locking which is partly responsible for the non-sinusoidal, and thus harmonically richer, output of heterodyne theremins in the lower pitch registers. Although the limited response distance of Phil's unit may be viewed as objectionable, he pointed out that he had become familiar with it and had, in fact found its response characteristics beneficial, since his hand motion was limited while playing his bass guitar simultaneously. One attribute of Phil's Maestro(TM) which is not available in some of my designs is its ability to produce very high frequencies, extending well above the piccolo, which he tells me is quite useful for his presentations. Phil encouraged me to provide a pitch expansion for my instruments, at least one octave beyond the nominal 1760 hertz. To prevent too much "crowding," a transpose switch may be most effective.
On another note, I'm still contemplating making a high-quality instrument available as a minimum-assembly kit. I have received several inquiries on the subject, but I'll wait until I've succeeded in producing a prototype of exceptional quality. Until then, I've been recommending the Big Briar "Etherwave®" to those who would like to own a nice, inexpensive unit. Phil recently purchased one, and he has related his satisfaction to me. I understand that the Etherwave® was a central feature of the Portland festival. I am, as always, particularly interested in comments from both Big Briar Etherwave® and PAiA Theremax(TM) owners.
Since I work from borrowed network servers and accounts, (to which, incidentally, I owe a debt of gratitude to the Unidentified Flying Opera Company, et al), my replies to individual questions are often slow. I really do appreciate the correspondence from theremin aficionados, though, and I'd be especially grateful for any impressions from those readers who attended the Portland festival.
Arthur Harrison
October 1, 1997
©1997 by Arthur Harrison