AETHERPHON, global theremin family

Quoting David V <porphyrous@...>:

> > Secondly, on more mundane matters, how can I control the world with my
> > theremin? That is, can I get a midi converter for it? Mine is a
> > Wavefront case model. In fact Wavefront (if he is still going) do a
> > midi box for the theremin, but it's $600+.
>
> I think it depends on what type of converter you want.  Pitch to MIDI
> converters are expensive and I hear they don't work very well.  What
> seems more likely would be to affect some kind of retrofit for a control
> voltage output, which could then be used directly by any analog
> synthesizer with an CV in, or there are a few MIDI to CV converters
> (though I don't know if they go the other direction) that are much less,
> tending around $100.  I think Kenton used to make one of those.

Since the Wavefront doesn't have CV (Control Voltage) outputs, you 
would have to
convert the pitch to a CV and then the CV to Midi messages.

Pitch-to-Voltage converters do not work well with ACOUSTIC or 
polyphonic sources
because the converter must extract the note to be converted.  In an acoustic
setting, any reverb, ambience, or resonanant vibrations (i.e., guitar strings)
will mess up the conversion.

However -- a pitch-to-voltage converter works GREAT with a pure 
Theremin signal.

(this next paragraph is technical -- beware! :) )

In fact, the Paia Theremax's CV output is created from the Tmax's internal
pitch-to-voltage converter.  If you check Paia's website and the schematic for
the Theremax, look at the circuit in the area of IC1.  The Theremax's pitch
signal is input to a comparator chip that outputs a pulse wave at the same
frequency as the input.  Besides the pulse wave's use on the bright 
side of the
timbre control, the pulse wave is also used to charge a capacitor.  Since the
capacitor discharges at a set rate and the frequency of the pulse wave 
changes,
then the amount of charge present in the capacitor is proportional to the
frequency.  Send that voltage thru another cap to remove the "ripple" and
voila: you now have a DC voltage proportional to the pitch!

Once obtaining a CV, in order to implement MIDI, the next step would be to
convert the CV to MIDI.

Since my Theremins have CV outputs, I am considering ordering the Paia "Midi
Brain" which is a Voltage-to-Midi converter.  I'm not sure how well it will
work however it is inexpensive so, what the heck!

Another possibility is to create a converter that converts CV to 
resistance that
would, in turn, be compatible with a breath-controller input.  I have played
with this a little bit with patch cords, alligator clips, etc... however I'll
have to do some serious breadboarding I spose.  I have heard that optocouplers
work for this application.

Has anyone been able to accomplish this?  Would appreciate any information!

The TOUGHEST thing about the whole Theremin / Electronic music field is to
balance musical projects with technical projects (and day jobs, mowing the
lawn, etc etc).

OK -- regarding the original question about the Wavefront.  It seems that
Wavefront sells the converter for around $495 according to their website.  I
s'pose with shipping and installation you are pushing the $600 price 
point. And, yes, that seems a bit pricey.

I will keep you posted on my MIDI-brain project -- though it will be a summer
project.  I think it would be easy (only a few bucks) to add a Pitch-to-cv
front end to the MIDI brain and I'll keep you posted on this.

Good day to all!

-- Kevin