Has anyone done this?

Posted: 1/19/2008 11:13:32 PM

From: Connecticut

Joined: 10/10/2007

Use some kind of mixer and a theremin to have an input signal ride atop the waveform of your theremin's output signal?

For example if there is no input signal the theremin's output will sound normal (for a theremin) but if you played an opera song into the second input you would be able to use the theremin to control the pitch of the opera singers.

I'm building a modified theremin that has an input jack where you plug in any audio source and it will output that source on your theremin's signal resulting in a pitch modulated output.

If you don't understand or are interested feel free to ask questions.
Posted: 1/19/2008 11:58:23 PM

From: Undisclosed location without Dick Cheney

Joined: 2/21/2005

It sounds like you're describing a vocoder.
Posted: 1/20/2008 2:30:39 AM

From: Germany, near Munich

Joined: 11/20/2007

...well, I did something like this with the Doepfer-modules...

...if you have the modules, playing with different combinations is really fun - but it gets expensive quickly, so you have to do careful planning...

...easier would be to route the theremin into your computer and then modulate the signal there (I did this with Ableton on a Mac)...
Posted: 1/21/2008 3:55:42 AM

From: Bristol, United Kingdom

Joined: 12/30/2006

Wait... how is what you're describing a Theremin in any sense of the word?
Posted: 1/21/2008 3:34:49 PM

From: Connecticut

Joined: 10/10/2007

I'll just buld it and make a video lol, then you'll understand.
Posted: 1/22/2008 12:50:54 AM

From: Fresno, California USA

Joined: 3/26/2006

I do believe there is a modification of the Theremax described at the PAIA web site that will do this.
Posted: 1/29/2008 6:48:23 PM

From: Toledo, Ohio United States of America

Joined: 2/22/2006

I, believe that the PAiA T-Max mod of which you speak is to allow the player to hear audio input that can be passed-thru to the T-Max audio output to an amplifier. This mod allows a player to practice a piece with minimal connections. I, may be wrong but, I do not think so.
What Zsy is talking about, might be a completely new form of theremin--- but, his details could use further explanation.
Good Luck!

Posted: 2/15/2008 12:07:51 PM

From: Escondido, CA

Joined: 2/6/2008

If any of you are still working on this project, you might want to check out the SSM2018. It's a bit pricey, but it works very well as a variable gain amp.

Posted: 2/15/2008 1:12:57 PM

From: Kansas City, Mo.

Joined: 8/23/2005

If you acquire a theremin with a CV out, you could, in turn, process that through a CV to MIDI converter. You could then assign the CC messages to a pitch bend function.

Bottom line is that you are using the theremin as a pitch bend device -- and you may have better luck just using a mod wheel or ribbon controller.

[i]-- Kevin[/i]
Posted: 3/21/2008 10:57:40 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

Yes - I am interested! If you have a way of doing this real-time, then it is facinating!

So - let me check.. You put a signal in (lets say a complex vocal monophonic waveform of 1kHz) and you can shift the pitch of this waveform using the position of ones hand reletive to the 'theremin' pitch antenna?

Note - A Vocoder will not do this.. it will only 'map' the harmonics of the input waveforms against each other. Also, feeding external audio into the ring modulator used to get the difference between the reference and pitch oscillators WILL NOT DO THIS! (I think this is what you have in mind) - It does produce an extremely interesting effect, but it does not shift the pitch of the input signal.. With no external input, the output would be the 'normal' theremin.. With an external audio input, the output would be complex.. I think it would be [T = Theremin pitch] [X = External waveform pitch + harmonics] Output = T+(T+X)+(ABS(T-X)) due to there being an output from reference and pitch oscillators = (REF+PITCH)which is high frequency and thrown away, and DIFFERENCE(REF,PITCH) which is the normal theremin audio output... This would modulate with the external signal giving Sum(T,X) and Difference(T,X).

If T and X were fed into a 2nd ring modulator (not involve the first modulator) the output would be Sum(T,X) and Difference(T,X) and T would dissapear from the audio output.

My advice to you is this - IF you really have a simple way to shift the pitch of complex waveforms (and talking about audio like polyphonic opera, which is indeed complex) then file a patent application on the idea before you talk about it! I have a patent (in last stages) on an "Analogue Function Duplicator" which will do what you describe, but only for pre-stored functions and waveforms, not on real-time input signals.

It is possible to do what you are describing by using a fast DSP - but there are still some difficulties .. like latency, particularly with fast changing 'reference pitch' signals.

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