The Theremin sound is produced by heterodyning. There is a fixed frequency 
radio-frequency oscillator, and a variable frequency radio-frequency 
oscillator controlled by one hand. The audio frequency beats between the two 
RF oscillators (sum and difference tones) are heard. In audio signal 
processing terms, perhaps this could be modeled by amplitude modulation with 
some waveshaping distortion, or simply by a sine oscillator passed through 
waveshaping distortion.

It would also be very easy to write a new opcode in C or C++ with 
high-frequency oscillators (based on difference equations) to model the 
Theremin directly.

Regards,
Mike


----- Original Message ----- 
From: "Mahound" 
To: 
Sent: Wednesday, January 16, 2008 4:40 AM
Subject: [Csnd] Theremin sound


>
> Hello.
> Does anybody have information about the waveform produced by the Theremin? 
> I
> tried to google, but some places say it's a sinewave, and some others that
> it's not exactly it (and it in fact sounds richer). However, I cannot find
> any real analysis of the timbre of this instrument (weird...). Aren't 
> there
> any csound orchestras for that?
>
> Cheers,
>
> Pedro
> -- 
> View this message in context: 
> http://www.nabble.com/Theremin-sound-tp14875977p14875977.html
> Sent from the Csound - General mailing list archive at Nabble.com.
>
>
>
> Send bugs reports to this list.
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
> csound" 

Pedro Ferreira wrote:
> Hello.
> Yes, I've read that it's achieved through heterodyning. But in this
> case we're left again with a sinusoidal (which goes against Joseph's
> mail). I guess the secret is the kind of filtering that the signal
> suffers. What kind of distortion are you talking about?
> 

Looking at the first track on the OHM disk set, (Clara Rockmore, "Valse 
Sentimentale" - and played ~extremely~ sentimetally!)  it is a filtered 
sawtooth (very few harmonics). Difficult to be more precise with all 
that vibrato.

Richard Dobson

I just looked at the output of a PAIA Theremax on a scope. It looks just 
like a sine wave except at really low frequencies where the positive peaks 
are gently flattened (which might be caused by the electrolytic capacitor on 
the output being too small). This theremin uses four coils. It also has a 
tone control which mixes a squarish wave with the sine wave to get a more 
triangular output.

Martin



Pedro Ferreira wrote:
>OK... we currently have three theories:
>- half-sine
>- sinusoidal through waveshaping distortion
>- filtered sawtooth
>
>(perhaps the last two ones are compatible?)
>
>But I heard that Rockmore's sound is slightly different from the
>"classic" theremin.
>
>Any ideas?
>
>Pedro
>
>On Jan 16, 2008 4:03 PM, Richard Dobson  
>wrote:
> > Pedro Ferreira wrote:
> > > Hello.
> > > Yes, I've read that it's achieved through heterodyning. But in this
> > > case we're left again with a sinusoidal (which goes against Joseph's
> > > mail). I guess the secret is the kind of filtering that the signal
> > > suffers. What kind of distortion are you talking about?
> > >
> >
> > Looking at the first track on the OHM disk set, (Clara Rockmore, "Valse
> > Sentimentale" - and played ~extremely~ sentimetally!)  it is a filtered
> > sawtooth (very few harmonics). Difficult to be more precise with all
> > that vibrato.
> >
> > Richard Dobson
> >
> >
> >
> >
> > Send bugs reports to this list.
> > To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
>csound"
> >
>
>
>Send bugs reports to this list.
>To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
>csound"

As it would have it, I started to dabble with recreating a theremin waveform
a few days ago.  Haven't gotten too far because of time restraints.  I went
ahead and created a graph of the output from the Big Briar Etherwave with
various settings.  You can download it here:

http://www.thumbuki.com/images/fullsize/BigBriarEtherwaveWaveforms.gif

Hopefully it will help.  And I'm personally going to be keeping track of
this thread as I continue to move forward.

Best, 
Jake 
---- 
The Csound Blog 
http://www.thumbuki.com/csound/blog/



Mahound wrote:
> 
> OK... we currently have three theories:
> - half-sine
> - sinusoidal through waveshaping distortion
> - filtered sawtooth
> 

-- 
View this message in context: http://www.nabble.com/Theremin-sound-tp14875977p14887220.html
Sent from the Csound - General mailing list archive at Nabble.com.

The plot thickens...  I briefly blogged about this thread yesterday, and then
matrixsynth.com was nice enough to post a link to it.  I got a response in
my comments from GordonCharlton that lead me to more information about
emulating a theremin.  Thought it might be useful to the others in this
discussion.

Waveforms of (a newer) moog etherwave 
http://www.flickr.com/photos/8666613@N04/2199492524/

theremin effects curves
http://www.flickr.com/photos/8666613@N04/sets/72157601954673258/

ThereminWord: "theremin emulation discussion on csound mailing list"
http://www.thereminworld.com/forum.asp?cmd=p&T=3104&F=1

comments @ thumbuki.com
http://www.thumbuki.com/20080116/big-briar-etherwave-waveforms.html


Best, 
Jake 
---- 
The Csound Blog 
http://www.thumbuki.com/csound/blog/



Jacob Joaquin wrote:
> 
> As it would have it, I started to dabble with recreating a theremin
> waveform a few days ago.  Haven't gotten too far because of time
> restraints.  I went ahead and created a graph of the output from the Big
> Briar Etherwave with various settings.  You can download it here:
> 

-- 
View this message in context: http://www.nabble.com/Theremin-sound-tp14875977p14924056.html
Sent from the Csound - General mailing list archive at Nabble.com.

Hello List

It seems that all the evidence is pointing away from the half-sine-wave 
theory!

Just for the record, though, (and to prove I wasn't completely making it 
up) I think I managed to find the video source which I originally looked at:

http://homegarden.expertvillage.com/videos/theremin-special.htm

Since a recent reinstall it doesn't seem to want to play on my computer, 
but there is a transcript at the bottom of the page.

Yours,

Joe

Jacob Joaquin wrote:
> The plot thickens...  I briefly blogged about this thread yesterday, and then
> matrixsynth.com was nice enough to post a link to it.  I got a response in
> my comments from GordonCharlton that lead me to more information about
> emulating a theremin.  Thought it might be useful to the others in this
> discussion.
> 
> Waveforms of (a newer) moog etherwave 
> http://www.flickr.com/photos/8666613@N04/2199492524/
> 
> theremin effects curves
> http://www.flickr.com/photos/8666613@N04/sets/72157601954673258/
> 
> ThereminWord: "theremin emulation discussion on csound mailing list"
> http://www.thereminworld.com/forum.asp?cmd=p&T=3104&F=1
> 
> comments @ thumbuki.com
> http://www.thumbuki.com/20080116/big-briar-etherwave-waveforms.html
> 
> 
> Best, 
> Jake 
> ---- 
> The Csound Blog 
> http://www.thumbuki.com/csound/blog/
> 
> 
> 
> Jacob Joaquin wrote:
>> As it would have it, I started to dabble with recreating a theremin
>> waveform a few days ago.  Haven't gotten too far because of time
>> restraints.  I went ahead and created a graph of the output from the Big
>> Briar Etherwave with various settings.  You can download it here:
>>
> 

Pedro Ferreira wrote:
> Cool video. Well, your wave actually sounds like a Theremin... so, I
> see no reason to reject it as a valid hypothesis :).

Great! Well, that's all I really wanted to hear...!

Joe

I just want to reiterate what Pedro said, because I do think your method does
sounds very much like a theremin.  I even posted a link to "Poor Little
Robot" on my blog back in April, as I really love the tune:
http://www.thumbuki.com/20070423/poor-little-robot.html  So I hope you don't
think I was trying to to disprove your theory, or anyone elses by posting
waveforms that contradicted your claim.

I guess my interest in recreating that theremin sound is being able to
emulate as many micro variables as possible, including that of different
players.  In the end, I want a theremin instr that I can call my own, with
its own personality and nuances.  This means I'm taking everything said in
this thread very seriously.

Best, 
Jake 
---- 
The Csound Blog 
http://www.thumbuki.com/csound/blog/




Joseph Sanger wrote:
> 
> Pedro Ferreira wrote:
>> Cool video. Well, your wave actually sounds like a Theremin... so, I
>> see no reason to reject it as a valid hypothesis :).
> 
> Great! Well, that's all I really wanted to hear...!
> 
> Joe
> 

-- 
View this message in context: http://www.nabble.com/Theremin-sound-tp14875977p14950384.html
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