Moog Music Theremini Reviews

Hello Hewson,

Yes, envelope following can produce a facsimile of the volume envelope - but it adds a lot of latency to the response, and works poorly at low frequency.... But it certainly is a possible way of doing things if you had no other choice.

IMO, omission of separate volume and pitch CV's is a mistake - but Moog probably needed to trim back from  including this for cost reasons (may have been more than just the cost of a socket - might have needed an extra DAC) and IMO having assignable CC from the theremini MIDI was a good solution ... It really is easy to have a small MCU which eats MIDI data and outputs CV, and such an add-on could be produced at low cost if one wants to drive a synth that doesnt have MIDI-CV built in.

For me, (assuming theremini CV works) it (and simultaneous MIDI CC) are the most interesting and useful features of the theremini - I have a 1V/Octave voltage controlled analogue heterodyning theremin design, and adding a MCU to derive volume data could give a complete true analogue theremin voice to the theremini - ( The reason I never moved to producing this voice was its (high) cost - But I have been working on reducing this.)

Rather than having to produce both the "controller" and "voice" sections, the "voice" could be driven by the theremini or EW+.. And it could output Volume CV as well so that other voices could be produced from modular synth bits.

But it all ( the whole use of the theremini with analogue synths) hangs on the fact that Moog has really implemented consistent 1V/Octave CV output - Im sure they must have.

Its (IMO) the theremini which would really benefit from a heterodyning voice - the EW+ already has this.. But the advantages of CV (being able to detune voices from each other, shift octaves and sequences etc) are, in my view, far more versatile and has far more potential than MIDI ever can for theremin application.

Fred.

hi fred,

But it all ( the whole use of the theremini with analogue synths) hangs on the fact that Moog has really implemented consistent 1V/Octave CV output - Im sure they must have.

i had my real troubles with a minitaur and a slim phatty and the 1v/oct. the slim phatty needed about 1.27v/oct! but that's now fixed with a trim-pot. and the minitaur can be calibrated by firmware (sysex). in one of the emails i had with moog, they wrote me this about the theremini: 

"The 1V/Oct is an old standard invented by Bob Moog back in the 1950’s, and when you first start working with it can be a little hard to understand. But the thing to remember is that all analog circuits are unique, and need to be calibrated to be precisely at the specs they were designed for. The Slim Pitch CV input was designed for use with an expression pedal originally, and then later we realized a lot of folk wanted to run it with modulars etc.
 
The Theremini CV out is not (currently) designed for pitch control either. It runs an output of 0-10V, but it is not necessarily following the internal pitch of the Theremini itself."

whatever that means, i thought, if other companies can produce versatile small mid/cv keyboards/sequencers to controll " animoog"under 200euros, moog should have built a theremin with all possible features of midi in/out/through, 2 cv outs, audio in/out/pre-listening, mic stand...for the price they want for a minitherethingy.maybe some kind of a cool-looking ipad connector with antennas on it would have done the job for most people.LOL!!

i still wait to get my hands on/off a theremini and meanwhile i keep playing my well tempered  ew+ through a mfos mini-synth an enjoy it very much.

dani

this pitch / voltage relationship wierdness makes me wonder if it is possible that the pitch cv comes from the analog heterodyning side (pre-digital engine)??  Which might actually give it a faster response than the e+'s frequency counter pitch cv approach...  that would be worth something if there were an adjustment pot for the cv out and a nice large playable pitch field...!

""The 1V/Oct is an old standard invented by Bob Moog back in the 1950’s, and when you first start working with it can be a little hard to understand. But the thing to remember is that all analog circuits are unique, and need to be calibrated to be precisely at the specs they were designed for. The Slim Pitch CV input was designed for use with an expression pedal originally, and then later we realized a lot of folk wanted to run it with modulars etc." -xtheremin8

Dani, thanks for the above.

This is utterly depressing though!

I have an old Moog synth (Prodigy) and, apart from when I repaired one VCO after buying it (the reason I was able to get it cheap) I have never needed to trim the VCOs since - It has tracked (after initial 10 minute warm-up) 1V/Octave perfectly (in fact, it tracks fine even straight after power-up, but I have tested its stability only after warm-up). I have an old Novation analogue (2 VCO's) that track 1V/Octave perfectly, and I have 16 (Curtis) VCO's in my Akai poly synth that track 1V/Octave perfectly - I have only ever needed to adjust the one (repaired) VCO on the Prodigy, and one of the VCO's in my (bought faulty) Akai once since I owned them (> 10 years).

There is NO excuse for "1.27v/oct" from a new Moog instrument! This is a cumulative 3.24 semitones/octave error!

The "when you first start working with it can be a little hard to understand." is just pure BS! and the "need to be calibrated to be precisely at the specs they were designed for" begs the question - "WHY THEN didnt Moog calibrate the instrument precisely at the specs it was designed for" ???

I dont understand whats going on - Are the new Moog instruments REALLY analogue? - Because, if they are really analogue, if each module in the synth has its own exponential converter, THEN the whole system - EVERY module, MUST track the same precise cv the instrument is specified for, and the whole "CV input was designed for use with an expression pedal originally" becomes moot -

The whole "script" is just damning IMO .. Its sort of reads like this to me: "We have a load of designs from the late Dr Bob Moog which we are modifying and fitting into our new products - but this is old 1950's stuff we really dont like - Our engineers are into digital technology, and dont have knowledge of or interest in old analogue stuff even at a basic level - we really dont know what were doing, and we really dont care - we are going digital.. If some users want 1V/Octave, they will just have to void their warranty and fiddle with the instrument themselves"

Doesnt Moog see the recent revival in CV synths and modules? Is the "New Moog" so stupid that they think they can pass off such rubbish onto a market that's growing and becoming more aware of the old technology and what it means? Do they really think now is the time to go digital with inferior digital products, and that the Moog name will give them anything other than disadvantage in this sector ? - Does Moog REALLY believe that they can now produce CRAP analogue implementations and utterly ignore the standard Bob invented, and let the Moog name carry them, while they disgracefully flout the standards THEY established?

When Moog specifies a product as having "CV Out" or "CV in" People expect (AND HAVE THE RIGHT TO EXPECT) this CV to comply with (at least) The MOOG STANDARD! - If it is adjustable to comply with the Buchla (1.2V / Octave) or other standards, that would be a bonus - BUT FOR SUCH INPUT / OUTPUT to NOT COMPLY WITH ANY STANDARD and not even be consistent or linear... DISGRACEFUL!!!

As for "The Theremini CV out is not (currently) designed for pitch control either. It runs an output of 0-10V, but it is not necessarily following the internal pitch of the Theremini itself."

Well, this says it all! - " not necessarily" - What the hell does that mean? It follows the pitch if your lucky? It follows the pitch on some settings or when the moon is in a particular phase? it "follows the pitch" only at one pitch point ;-) ? It never follows the pitch, but its less damning if we say "not necessarily" ?

"Theremini CV out is not designed for pitch control" - What the hell is it "designed" for then? .. Is it perhaps
"designed" to increase sales because people are MISLED into believing they could use it for pitch control ????? - Is this perhaps also true about the Pitch CC output from MIDI - Does this actually track pitch? Or is it just a CON like CV output?

There was a time that people bought Moog analogue synthesisers and modules because they came from a company that knew analogue. From the above, it looks like one would be safer buying a cheaper synth / module from someone like MFOS.

Sadly, it looks like Moog died with Bob.

Sorry Synthguy - You were right about the CV being (my words) CRAP!

Fred.

"this pitch / voltage relationship wierdness makes me wonder if it is possible that the pitch cv comes from the analog heterodyning side (pre-digital engine)??  Which might actually give it a faster response than the e+'s frequency counter pitch cv approach...  that would be worth something if there were an adjustment pot for the cv out and a nice large playable pitch field...!" - Hewson

I fear this is likely to be wishful thinking.. Read Moogs own words about the CV : "Theremini CV out is not designed for pitch control" -   Somehow, I fear that these are probably some of the few words from Moog we can trust!

All the features (linearity, span etc) probably come from the "engine" - IF the CV is derived directly from the heterodyning front-end, I would guess that its of little use for pitch control.

I might be wrong - who knows...

Anyway, Im probably not going to say any more on this thread.. There's now absolutely nothing about the theremini (or in fact any modern Moog instrument) which is of any interest to me - The theremini is of no use to me musically, no use as a controller, and its too expensive to buy as a toy for my grandchildren.

Fred.

In case any one is just now tuning in, here is a summary, in slightly less technical speak.

The Theremini has a heterodyning analog backend which is interfaced by the player...

It has a digital sound engine that uses technolgy from Moog Music's Animoog iOS app.

[Edit: the following statement yet to be verified...

The Control Voltage output of the Theremini is derived from the analog side of the instrument.]

There currently exists no consistent relationship between the pitch coming out of the Theremini and its Pitch CV output (except that they increase and decrease in the same direction).

The CV output may "not necessarily" adhear to the 1 Volt per Octave standard and even if it does, the relationship to the Theremini's pitch output would change every time the instrument's MIDI range was modified.  Therefore the CV connection can only be used as a low precision gesture control for now.

"The CV output may "not necessarily" adhear to the 1 Volt per Octave standard and even if it does, the relationship to the Theremini's pitch output would change every time the instrument's MIDI range was modified.  Therefore the CV connection can only be used as a low precision gesture control for now." - Randy

If CV doesnt track theremin pitch, then, from a theremin, "1V/Octave" would be meaningless anyway - The only octave reference is the octaves produced by the theremin - the only other 'reference' could be capacitance or distance from the antenna.. and this could never be specified in terms of V/Octave, it could (if linear) only be specified in terms of V/Distance or V/Capacitance.

The ONLY usable reference is therefore the theremini pitch... The only use for CV (in terms of controlling pitch) is therefore if it tracks this pitch... IF it tracked this pitch (no matter how or what internal voltages etc were used) and exponentiated this, it would be simple to add any required offset when changing span or whatever, and produce the correct 1V/Octave output.

[ EDIT - >> The following is now in doubt...

IT DOESNT! - And I suspect that Hewson is right - to a degree - I suspect the raw heterodyned signal is converted to a voltage without any linearization or exponentiation - A voltage which has NO relationship to pitch and no linearity... This way the CRUDEST POSSIBLE and UTTERLY USELESS "CV" could be provided.(it is, in fact, the same raw signal fed to the digital engine - but the digital engine processes it to provide musically useful data - this processing is not applied to the CV, and therefore the CV, lacking any processing, either analogue or digital, is even more useless than if one took the EW+ period voltage and fed that out as a CV without putting it through the final, essential log converter. 

Therefore " Theremini CV out is not designed for pitch control " must be taken as true - furthermore, it can be assumed that Theremini CV out cannot be used, in any reasonable way, for any form of pitch control.

<< -  I now think the Moog statement is probably an error. <<  End EDIT]

Fred.

Fred, I do understand what you mean now... The output pitch is the only reference from which the "octave" in Volts per Octave can come from.  In my head, ever since I first heard about the CV in the Theremini,  I never once thought of the CV 'following' the output pitch.  We probably would not be discussing on this topic, if everyone thought that to begin with.  The Theremini User Manual might be a good place to put this kind of useful information... but as we know, it is not exactly "comprehensive".

When bichuelo returns, I'm interested to hear how great the difference is between the Theremini (in full range un-quantized chromatic scale mode) and the attached synth.  

Wow. I popped back into see how things were going, and I just can't believe how far off the track you guys have gotten. Sitting here this evening enjoying a martini, this has made for some VERY entertaining reading. Cheers!

Now, to business.

Of COURSE the CV out tracks the pitch of the Theremini. It should have been obvious from the first crude measurements I made, showing a two octave spread giving 2.5 per octave @5V. That means each octave increases 2.5 volts.

Here's some FACTS, which I hope will get you guys back on track again, and tone down some of this wild rhetoric.

1) CV Pitch correction, when turned on, provides the necessary relationship between Theremini pitch and the CV out. The 10V setting provides the largest range. Use that. As the pitch correction knob is turned up, the CV mirrors the steps of the selected scale.

2) Changing the low and high note range will "tune" the scaling. Setting the low note to the lowest setting and the high note to A#8 will get very close to 1V/Oct (but not quite perfect). Using a simple dual opamp circuit to adjust the scale and reset the range of the CV will allow for precise tracking of the Theremini and a typical synth. With this, you can define any range you want for the Theremini, and scale the synth to follow it, IN TUNE.

Fred, I know you must know how to build one of these, so show the people how! I made a quick and dirty version on a breadboard for my purposes, and will build it into a box later.

3) I've been able to get an SCI Pro One to track anything from a 1 octave spread, to a 6 octave spread. Perfectly. I realize this isn't the ideal solution, but it can be easily accomplished, which is pretty good for a CV that is designed as a general purpose controller for stuff like Moogerfoogers (as they show in the connections example), as I've said in previous posts. Sounds pretty neat, too. Since the range is a global setting and not remembered per preset, I think that many users will probably set a range that feels comfortable and stick with it, so rescaling the CV may not be continuously necessary anyhow.

Now you all know what "not necessarily" means in this context.

Be excellent to each other.

"Fred, I know you must know how to build one of these, so show the people how! I made a quick and dirty version on a breadboard for my purposes, and will build it into a box later." - Synthguy

Synthguy - Glad to see you back! I felt a bit rotten at having been so gruff to you!

I know how to design / build any circuit to manipulate / scale / alter a linear CV.. How to take a 1.2V/octave CV and scale it to 1V/octave with a simple potentiometer, or a 1V/Octave into an opamp to get 1.2V/Octave, or take 1V/Octave and shift the CV up or down to produce any interval shift...

{Added}-> I have never ever seen anything like 2.5V/octave! (this would only allow 4 octaves in 10V) and I think it likely you got this wrong..   - but a couple of resistors/ trimmer/ and perhaps buffer would knock that down to 1V/Octave.

But all of the above ONLY work if the CV linearly tracks the pitch.

{Added}-> IF you are saying that, when you select a span of 4 octaves, and select 10V output, the CV is 10/4 V/Octave, then this is just about the craziest CV scheme I have ever seen! - But it would be usable with a simple custom designed switchable attenuator - Also, if the above is how it works, then selecting 5 octaves and 5V output should give you 1V/Octave without the need for any external circuitry or modifications!

And if it does track the pitch, then Moog's statement "" Theremini CV out is not designed for pitch control "" is not true - because CV usable for pitch control doesn't just happen by accident - it needs to be designed, and carefully designed - its not a "natural" relationship that just falls out of the circuit.

IF what you say is true - IF, with a simple scaling circuit, you can get the CV to accurately track the pitch over 5 or more octaves, THEN the CV out is linear and HAS been designed for pitch control.

I really dont know what the truth is. You say that when pitch correction is turned on, the CV tracks this - Moog says that this isnt implemented. You say CV tracks the pitch, Moog says it doesnt, and that CV out is not designed for pitch control. You say that with a simple opamp scaler, you can get 1V/Octave.......

So I DONT KNOW! And anyway I dont understand why, if a tracking CV is present inside the theremini, Moog wouldnt just build an extra tiny bit of additional circuitry (as you have done on breadboard) inside the theremini so that it puts out 1V/Octave - it makes absolutely no sense.. None of this makes any sense!

So I will say no more until some others feed back their experiences - Because, as it stands right now, I have read reports that (a) It doesnt track pitch. (b) It does track pitch (c) it sometimes tracks pitch (d) it tracks pitch, but the CV isnt 1V/Octave. And the only information from Moog seems (to me) to confirm that it doesnt track pitch.... But it seems I cannot trust anything said by anyone, and perhaps Moog is saying something detrimental about the theremini which isnt true, because whoever wrote the email didnt know what they were talking about... WTF!

Fred.