Best sounding Theremin question

"This instrument has the peculiar tonal richness unique of tubes..."

I just don't buy that.  For all I know it sounds awesome, but (though some recording engineers, many audiophiles, and most electric guitarists will tell you different) tubes haven't cornered any market in tone.

And good lord they must drift like crazy with all that heat.  Anyone here with a tube Theremin want to comment on that issue?  I'm very curious.

Had Leon Theremin been born ~40 years later (like Bob Moog) he almost certainly wouldn't have used tubes (like Bob Moog).  And we'd probably have ad copy that reads "This instrument has the peculiar tonal richness unique of germanium transistors..."

Sorry everyone for the rant, this is one of my personal bugbears and I probably need to get over it or move on or something.

heh, it akes my RCA at least 20 mins to warm up and after that it is quite stable.  First 5 mins are totally unplayable.  Kep is stable in about 10-15, but the drifting creeps along in slower/ smaller increments.

I totally agree about the "magic" of tubes-  perfect example is the Forbes tube theremin (my first build**)  uses 12au7's.   A terrible, unplayable waste of time.    Tubes can sound better but it has to be a well designed circuit to begin with. (also early transistor can sound better too,  funny, some are pretty rare and highly sought after especially in the boutique pedal crowd - with prices higher than tubes)   It is just the inefficiency in design and limitations of manufacturing, that makes the old stuff sound better- kinda like how piano tuning strays slightly off key toward the upper register. The (slight) imperfect-ness is more pleasing to our ears.   Also why "Autotone" sounds sucky and Jar Jar is creepy- the "Uncanny Valley" 

Tubes can also introduce a lot of garbage in RF circuitry- can be highly susceptible to interference = birdies/ chirpies.

However, It is a undeniable fact that tube just look way darn cool.

Im no engineer but, I think most of what makes an RCA tone so desirable is coming from the oscillators (armstrong) and mixer circuits.  A few months back on levnet, theremin sage,Uncle Howie,  posted what he would like to see in a new theremin design:    No tubes, using all transistors or mosfets; copy the osc and mixer exactly (coils n all) from the RCA; use the Moog melodia volume circuit; and lastly small pi wound inductors for the antenna coils.      

(** heh interesting story- all the parts were given to be by a coworker.  he saw the theremin documentry in the 90's -  got all stoked,bought all the stuff and could never get it working. Humiliated by the failure  he tried giving it away, several times , but it was always give back unfinished.  It sat on an antique wooden tugboat for at least 10 years ( I worked at a maritime museum)  until he found out I was into electronics and I mentioned thermins)

When a new theremin design comes "to market", all red flags should be activated as long as none of the renowned professional theremin players (for example Lydia Kavina, Carolina Eyck, Thorwald Jorgensen, Peter Pringle, Thomas Grillo) hasn't tested, judged and approved it.

Most new designs come actually from very good engineers who mostly have not enough musical experience and culture, while a professional player has already seen and played lots of different instruments in his life and knows better what feels at least "correct" besides purely technical considerations and data.

I have experienced that myself when building (and later optimizing) Thorwald Jorgensen's instrument. Although I consider my own musical knowledge and years long theremin experience as not too weak, I have learned still a lot of things during the cooperation phase with Thorwald.

I really can't understand why people like Matthia Pegna who have perhaps the abilities to create interesting circuits don't look for approval by professional musicians already during the development phase which could improve the result and be helpful for future "amateur" clients in their phase of decision.

"heh, it akes my RCA at least 20 mins to warm up and after that it is quite stable.  First 5 mins are totally unplayable.  Kep is stable in about 10-15, but the drifting creeps along in slower/ smaller increments."

Thanks!  That's pretty consistent with how I remember radios and TVs from my childhood.

"Most new designs come actually from very good engineers who mostly have not enough musical experience and culture..."

This statement is true, and broadly so IMO.  It is quite rare for very good engineers (not saying I'm all that hot, but most are uninspired) who actively work on instrument development (a very tiny field) to also be a very good musicians on their target instrument, or even musicians at all.

One more reason for these engineers to cooperate with a professional musician. In ancient times (several hundred years before industrial production of music instruments became common) the instrument builders were commissioned by a musician to build an instrument for and with him. 

Industrial (in terms of not knowing who will play an instrument later) production can only start when there are commonly accepted quality standards. These don't yet exist for the theremin, it's too young and there are as many playing techniques as there are thereminists. On the violin side it's much simpler, only two variants of playing technique, the Russian and the French system have survived.

What makes a good theremin today? Armstrong tube oscillators overdriving a tetrode mixer into an inductive load without feedback as in the RCA? Phase comparators on fixed frequency xtal oscillators as in the Big Briar Series 91? CMOS frequency dividers as in the Etherwave Pro? The musicians don't care off all that.

They only expect that the instrument does what they want to do with it, not limiting them in their musical expression because of technical constraints. For many professional players, perfect linearity is not every time an absolute prerequisite. It's like on the violin whose tone spacing decreases the more higher you play on a string. Lots of practice and an adapted playing technique allows the violinist to hit the tones though. You have just to know your instrument. Knowing really your instrument requires practice and experience. Unfortunately Peter Pringle is right when he says sarcastically "On the theremin everybody is an expert". 

Thus the art may consist in distinguishing and filtering the true experts from the false...

Thierry wrote: "Thus the art may consist in distinguishing and filtering the true experts from the false..."

Unfortunately, the art of distinguishing the true experts from the false is yet another field in which everyone is an expert! LOL

I will add the latter to my collection of PP's aphorisms! ;-)

Thierry,

This afternoon I compared the vocal "AH" effect of the ELECTRO-HARMONIX Talking Machine using my SERIES 91A, the Etherwave Pro, the Moog Ethervox and the Goldberg RCA. 

There is about to be a rash of recordings, videos, etc., from thereminists of all sorts, all using the TM with their instruments and I was curious about how the results would compare with the Goldberg RCA.

Julius Goldberg's instrument has a particularly disagreeable sound as a result of the clumsy alterations made to it by previous owners. Not only that, but the sound morphs markedly over the four octaves of the theremin's range. While the TM will significantly change any sound fed into it, the pronounced harshness of Goldberg's instrument seems to work better with the device than the gentler, smoother timbres of the other theremins I have tried. 

There is a richness and depth to the sound that translates into a distinctive masculine quality that surpasses the results I was able to get using the TM with any other theremin. 

"While the TM will significantly change any sound fed into it, the pronounced harshness of Goldberg's instrument seems to work better with the device than the gentler, smoother timbres of the other theremins I have tried. " - Coalport.

This is no surprise! One cannot filter harmonics if the harmonics are not there - and the whole principle of formant filtering depends on having as wide a spectrum of harmonics from which the formant filters can 'tune' to those required for the vocal effect.

The larynx produces a waveform which can be quite closely aproximated with a 1/2 wave rectified triangle wave, slightly biased so that the 'flat' section has a slightly longer duration than the 'pulse' section.. This is NOT a waveform one usually sees from a theremin! - and it certainly can be a "disagreeable sound" if the unwanted harmonics are not removed or attenuated..

And this is the irony of vocal formant synthesis - The formant frequencies do not relate to the fundamental in any of the usual ways, so the most horrible sounding theremin may well sound best when played through a TM. If you have a lovely sounding theremin and want it to sound horrible so that it will sound lovely when played through the TM, start by simply 1/2 wave rectifying the audio.

What you need is a "wasp in a jar" type sound - The Enkelaar theremin switched to this mode will probably sound great through the TM.

The ideal would probably be to have a seperate distortion circuit between the theremin and the TM - one which allows adjustment of the pulse width and shape, ideally having a frequency dependant relationship.. a few components and a couple of knobs for adjustment - Hmmm.. perhaps I need to buy a TM!

Fred.

Prof. Maurice Martenot knew apparently about that. To make his Ondes sound more interesting, especially in conjunction with his "résonnateurs" (speakers with added mechanical components which have fixed resonant frequencies), he added circuits which allow to add weak ("souffle") or strong ("bruit") pink noise to the signal. This allows to trigger those mechanical formats even when the main signal does not contain the fitting harmonics.

I wonder if adding a small amount of pink noise to the theremin's signal would also greatly improve the results of the TM.