A polyphonic theremin!

Posted: 10/14/2008 7:24:46 PM
Vanegm

Joined: 10/14/2008

Hello, how are you all?
Well I am a student from Venezuela, trying to graduate on telecomunnication's engineering. So far I am doing good, but for the next month I have to make a polyphonic theremin. I have looked for some info on the internet but I haven't been able to find much.
If you know any website that could help me in the creation of a polyphonic theremin, could you be so kind in letting me know about it please?
Thank you very much!
be well!
Posted: 10/15/2008 1:28:53 AM
TomFarrell

From: Undisclosed location without Dick Cheney

Joined: 2/21/2005

Lev Termin apparently told Clara Rockmore, toward the end of their lives, that he had managed to create one but nobody could play it. Since then, nobody has created one. Frankly, if he, great genius that he was, only managed to produce one prototype and never got anywhere with it, I would say you should expect to have one heck of a hard time producing one as a school project.

I really recommend you pick a different project.
Posted: 10/16/2008 7:22:44 AM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

While not a true polyphonic instrument, at Ether Music 2005 Dan Burns, maker of the B3 theremins, showed us a three-voiced theremin that he had created.

My memory is a little fuzzy on the details now, but it was capable of playing up to three separate voices simultaneously (in unison).

This theremin had nineteen knobs, so I don't recall what all of them did, but I am pretty sure each voice could be tuned separately.

I just occurred to me that perhaps Mr. Burns was hoping to interest Moog Music in his product.
Posted: 10/17/2008 1:34:54 PM
djpb_designs

From: Escondido, CA

Joined: 2/6/2008

As others have pointed out ... "define polyphonic..."

If you want to have a theremin that plays chords, you might be able to do that by using the theremin to trigger a synthesizer ... i.e. using a theremin with a MIDI output to control a MIDI synthesizer programmed to play the chords.

If you just want to play 2 separate notes, build 2 pitch-only theremins and skip the volume loop, or use a foot pedal volume control. Then you can use each hand for a different note.

Either of these methods you could more than likely accomplish in the time you need to complete this project. Other than that, you will have a long slow road ahead of you to develop something that someone can actually play music on.

Don
Posted: 10/18/2008 8:22:27 PM
unclechristo

From: Leicester, UK

Joined: 9/23/2005

For a polyphonic theremin I tend to put it through a hamonizer. You can either set the scale you want the hamonies to play in, or set the hamonies to follow a midi song, or just set a fixed set of intervals.
Posted: 10/19/2008 9:11:16 AM
Thomas Grillo

From: Jackson Mississippi

Joined: 8/13/2006

I also use harmonizers for poly theremin playing.

Just an update on Dan's polyphonic theremin, Back when I visited with Dan, and his wife last month, they mentioned that it had been damaged by Katrina when they were still in New Orleans.
Posted: 10/20/2008 7:05:05 AM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

As others have pointed out ... "define polyphonic..."

OK...from the dictionary...

Polyphonic - Having two or more INDEPENDENT but harmonically related melodic parts sounding together.
Posted: 10/20/2008 4:12:51 PM
djpb_designs

From: Escondido, CA

Joined: 2/6/2008

Harmonizer --- Missed the opportunity on that one :( About 30+ years ago I guitar player friend asked if I could build him something to allow him to sing a harmony to himself.

Never got far on that project. Now there's a few you can buy.

If this is what the guy who "has to build one for a senior project" has in mind, he'd be better to buy everything off the shelf and write a paper on how it works. Building this sort of thing "from scratch" would be a very long, involved task!

As for the "define polyphonic" comment ... you can create "extra voices" by using a digital counter clocked by your analog output, with its various outputs summed into the analog mix. Not exactly spectrally "pure", but it would be polyphonic ...

Don

Don
Posted: 10/24/2008 12:08:23 PM
omhoge

From: New York, NY

Joined: 2/13/2005

The times I've jury rigged my gear to produce a second independent (though usually harmonically dissonant) tone controlled by the volume loop, it was really hard to control for any sort of tonic music.

It was OK for non melodic sound scapes, but I think it would be very hard to make it coherently expressive with the two voices when one hand still has to control the dynamics for both. They'd never get the full expressiveness of a duet.

Of course I'd love to see a working polyphonic theremin and try it out, so please keep going!
Let us know how it goes.

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