Moog Theremini!

Fred,

Great idea. I'll try it with a Slim Phatty (all I have with CV in) and also try and do it a bit more scientifically (and compare against my Etherwave Plus).

Thanks

Rich

Hi Rich, and thanks! - Its been real frustrating having folks with 1V/Octave synths saying they would do the tests, but then just vanishing!

If my hypothesis is correct, and IF the theremini CV actually tracks its pitch, what we should see is:

1.) With theremini set to span exactly 5 octaves, and CV output set at 0-5V, a 1V/Octave synth or VCO should track the theremini pitch - it may need to be tuned, but the relationship between the theremini pitch and the synth pitch should be locked and not change over the 5 octaves.

2.) If the theremini span is then changed to say 7 octaves, then the pitch from the theremini will not track the pitch from the synth - a change of 7 octaves on the theremini will result in a change of 5 octaves on the synth - this will hold true whatever span is set on the theremini - with a 0-5V output, the synth will always span 5 octaves, regardless of what the theremini is set to span, be this 3 octaves or 7 octaves.

3.) Changing the theremini CV output to 0-10V, the synth will change 10 octaves for a full sweep, again, regardless of the number of octaves played (spanned) by the theremini - I do not believe (if my hypothesis is correct) that there is any way to get the theremini and (1V/Octave) synth to track each other when the theremini is outputting 0-10V.

4.) If my hypothesis is correct, the only time there is any possibility that a 1V/Octave synth will track the theremini is when the theremini is spanning 5 octaves and set to 0-5V CV output.

Fred.

hi rkram 53

 i had to get my slim phatty get modified for exact 1v/oct tracking! it didn't do so out of the box. they added a trim pot inside and now i'm fine. ( finaly added scope pics in "d.loosegears fantasies" )

;-)

" i had to get my slim phatty get modified for exact 1v/oct tracking! it didn't do so out of the box. they added a trim pot inside and now i'm fine." - Xtheremin

<The following opinion is based entirely on the assumption that the above is true and that no other mitigating factors were involved>

What more is there to say? When something as basic and fundamental as accurate 1V/Octave isn't there on "Moog" synth, but needs to be added with additional component/s, well, IMO it may have "Moog" on the fascia, but it aint the Moog I know.

No "Moog" synth should, IMO, pass QC if it doesn't track external CV at 1V/Octave.. Having a trim pot should be standard if this is needed to fine tune the interface .. But to skimp on this part and only add it if the customer complains - IMO that's a scandal! - And to provide a customer with an instrument that isnt correctly calibrated prior to shipping, and which has no easy user accessible means of correcting this is an outrage!

And I truly dont understand it - It makes me doubt the quality of the whole instrument.. You see, an analogue synthesiser is a collection of function blocks or "modules" - its effectively an analogue computer, each block performing some specific operation..

But the fundamental basic underlying essential aspect is that all modules must be calibrated to some standard they all share so as to track the control signals together - And with Moog, this standard has always been 1V/Octave.. So if the keyboard (or MIDI) outputs 1V/Octave, and the internal oscillators and filters accurately track this 1V/Octave, SURELY the one external CV input should also accept 1V/Octave !?

And if they cant even bother to check that, and if they ship high-end synthesizers which need modification and additional components just to track an external CV input, how can anyone trust them to be doing anything right?

Hell, with the digital interface on new Moog products, it would be easy to fit one digital potentiometer on the external CV input to allow this to be tuned - This would make the CV compatible with other standards and allow fine trimming of the 1V/Octave standard, particularly useful probably if interfacing to another Moog product which outputs "1V/Octave" which isn't actually right..

Fred.

fred,

finally!

more on channel cv's and synth stuff. :-.

Yes, I've seen some notes that their Slim Phattys are scaling 1 Volt to a seventh instead of octave (but that should be ok for the tests we want to run as long as we know the initial scaling). I just got mine so hopefully it is scaled 1V per octave. We'll see if that's been resolved by Moog in the process.

Rich

"finally! more on channel cv's and synth stuff. :-." Xtheremin

"Yes, I've seen some notes that their Slim Phattys are scaling 1 Volt to a seventh instead of octave " - Rich

Hmmm .. This is a theremin site, not a CV synth site! .. IMO, there has already been more discussion on CV than we should need.. Its only because the theremini CV appears to be dysfunctional that this matter has come up here.. But if it starts to get into discussion about synths in general, well - I suspect that some folks will get pissed off, with good reason! ;-)

At this time there are 3 threads (at least) devoted to the theremini or related matters - this thread which doesn't have a specific focus, Moog Theremini Reviews which I felt was getting obscured on the matter of CVs, and started the CV Thread to move subject away, and also started the Technical Hijack thread to keep this thread clearer of stuff people didnt want cluttering the thread..

But it just keeps rolling.. The trouble, I think, is that the theremini poses something of a dilemma to this community - its Moog, and we have all adored Moog ; its called a theremin - but it really isn't one ; it introduces synth technology, but the implementation needs technical understanding in order to evaluate it - knowledge not common within this community ; it implements pitch correction and tuning display and all sorts of bells and whistles - but the implementation / usefullness of these is questionable; But - most critical, it appears to be crap - a toy - a marketing con - a pack of lies - a hugely wasted opportunity, a 'thing' which has huge potential that has been buried under such a deep pile of shit that this potential cannot be realized.. And these factors combine to make this time-wasting debate self-perpetuating and steers this "debate" in bizarre directions, including technical and musical and ethical.

Post traumatic shock syndrome in one swipe from Moog at the theremin community - we are all (except for sensible folks like Thierry) wandering about in a dazed stupor, rather than just facing the facts - Some people will use this toy as a means of generating Animoog sounds and be happy with that (but they may as well get these sounds in a usable form from some software app) Newcomers to theremins could be put off theremins by this toy, a handfull of people on this planet may actually find it more useful than an Animoog app, and some kids may make their kind of 'music' with it and have fun...

But IMO the theremini has NOTHING for the theremin community, and it seems that thereminists are mostly coming to this same opinion..

And I really have nothing more to say on it, or on any "Moog" product created without Bob's input - I actually dont want to hear about phatty's that "track" at 1V/7th or anything "Moog" gets up to anymore - I dislike the sounds from the latest "Moog" instrument that was raved about here - to my ears its sounds vulgar, harsh and enharmonic - oh it looks cool, has loads of knobs and lights and switches, but I wouldnt swap my Moog Prodigy for it! - IMO even my Novation Bass-Station rack or my Akai AX73 or Juno 6 or my Siel Cruise or Farfisa Synthorchestra sound better - Even my Access Virus B and Korg Karma fully digital synths sound better TO ME - And I could pick any of those up on Ebay for less than a new Moog synth!

But its all down to taste aint it! ;-)

All I can do is repeat my past opinions I have expressed probably too often - My opinions upset people, and (at least one of) these people then target me and troll me wherever they can ..

Good luck with getting your theremini to talk to your phatty, Rich! - Sorry about the above, none of it was directed at you!

Goodbye.. I really cannot be bothered discussing any new "Moog" thing anymore. Perhaps my "inner Bob" is too stressed out by all of this :-(

Fred.

Fred,

So I did a bit of testing. Interesting results.

1. Calibrated the Theremini to myself as they say to (about 20" reach to the pitch antenna for me).

2. Set Theremini for range C2 to C7. I notice the Theremini appears to be playing an octave higher than the tuner indication. Not sure what that that is all about. Anyone else see that?

3. Measured antenna distance to my hand from the antenna (attached a snmall string to it so I could keep track of the distances) vs. voltage vs. what the theremini tuner said  for itself (measured C7, C6, C5, C4, C3, C2 (though actual pitches Theremini was playing were an octave higher - says my tuner and ear). Here are the results (rounding to about the nearest 0.1 V):

Note  Distance  Voltage

C7            .5"             4.9V

C6             3"             4.0V

C5             5"             3.0V

C4              8"            1.9V

C3             12.5"       1.0V

C2              31"         (but you have to pull back to 48" to get around 0V).

I've noticed this. The Theremini at times when you calibrate will not let you hit the lowest notes without going out of town. Maybe there's a bug in the calibration. Maybe i didn't wait long enough on the step to step back.

So I recalibrated and did it again and got better results (must have been a bit closer to the unit - it does seem to autoscale the voltage from your initial calibration distance - (Still everything was an octave higher than the Termini's tuner said it was).

Note  Distance  Voltage

C7            .5"             4.9V

C6             2.5"          4.0V

C5             4"             3.0V

C4              6"            1.9V

C3             8.5"        1.0V

C2              15"        0.05 

Now for my Slim Phatty. 

First I don't see a gate out on the Theremini which could be a big issue playing CV synths. I had to hook up a pedal to the Slim Phatty to gate a sutained note. Then I calibrated the Slim Phatty to put out C7 (what my tuners says is C7) at the closest antenna position. Here's the table for that at the first calibration:

Note  Distance  Voltage

C7            .5"             4.9V

C6             3.5"          4.0V

C5             6"             2.9V

C4              9"            1.9V

C3             17"           1.0V

C2            Never gets to C2 no matter how far I pull back.  

Close to a volt an octave here. So I did the Slim Phatty again after the second calibration and it agreed quite well with the Teremini's second calibration.

C7            .5"             4.9V

C6             2.5"          4.0V

C5             4"             2.9V

C4              6"            1.9V

C3             10"          0.8V

C2            Never gets to C2 no matter how far I pull back (only gets to F2). 

I could be off a bit here and there but it seems reasonably scaled 1 Volt per octave to me.

Rich

All,

I'm done on this topic as well. I have to get back to practicing the Etherwave. My Theremini goes on the shelf until Moog can scale it properly to be a decent portable practice instrument. I sent Moog a note on what they need to do to make it useful to a thereminist in my opinion. We'll see what develops.

Rich

Rich,

I cant leave without first saying thanks to you for this effort !

The results you give tend to align with my hypothesis - but I no longer care... the linearity is so bad that its useless anyway, even if the CV worked.

Again, many thanks -

Fred.