Superior to the Ethervox !? TWO

Gordon wrote:

I suspect it is the note-on event button which lets you conclude that it [the MIDI Wave] is "superior" to the ethervox. In that limited sense I would agree. A note event trigger is fundamental to MIDI and I consider it a very welcome development.

**************************

Gordon, I suspect from what you wrote above that you may not be familiar with all the "modes" of Ethervox MIDI theremin operation.

Bob Moog solved the problem of triggering note events in the Ethervox MIDI theremin in a very interesting and creative way that allows it to be done while playing, without touching the instrument or having to adjust knobs or push buttons.

There are four possible MIDI "modes" on the Ethervox:

PITCH MOVE MODE
CHROMATIC MODE
CONTROLLERS MODE
PITCH SMART MODE

In PITCH SMART MODE, as the left hand pulls away from the volume antenna, the amplitude of the volume control MIDI signal increases, just as the volume increases in a standard, traditional theremin. The instant the movement of the volume hand of the player is reversed, however, and moves toward the pitch antenna, in PITCH SMART a new MIDI "note on" message is sent with a "note on" velocity value equal to the last value displayed on the Ethervox performance screen. The "note on" number is determined by the position of the pitch hand in relation to the pitch antenna at the moment the "note on" message is generated by the volume hand.

With this approach, a "note on" command can be sent while playing with no need to leave the playing arc.

Through skilled use of PITCH SMART MODE, a thereminist can avoid attempting to pitch bend a MIDI receiver beyond its capabilities, and can maintain an even and consistent tone throughout the range of the piece being played. Many people who are unfamiliar with the way pitch bend information works, forget that with a sample of an instrument like a clarinet, the sound of the low 'G' is entirely different from the sound of the 'G' three octaves above it. The high 'G' is not just low 'G' pitch bent up three octaves.

If, for example, you were playing a sampled clarinet and triggering it with your MIDI Ethervox, and you wanted it to sound like a clarinet and not like a cat in heat in the back alley, you would use PITCH SMART MODE and change your MIDI note at intervals of about a major fourth. As with all things THEREMIN, your hand would need to be guided by your ear.

Of course, in all the modes in which it operates, the Ethervox performance screen tells you exactly what the instrument is doing at any given moment.

This thread continues from here (http://www.thereminworld.com/forum.asp?cmd=p&T=4699&F=1&p=3).


[i]Gordon, I suspect from what you wrote above that you may not be familiar with all the "modes" of Ethervox MIDI theremin operation.[/i]

This is true. Information about it is hard to find.

Yes, that sounds like a good solution. I did not know about it. Thank you for setting me straight on this. Presumably this means that you lose the ability to play diminuendos, but I recall your mentioning that the volume field was compressed and switch-like in the MIDI modes, so this would not really be an option anyway?


[i]The instant the movement of the volume hand of the player is reversed, however, and moves toward the pitch antenna[/i]

Should that read "toward the *volume* antenna"?

This is just to let people know that, in the light of the removal of all the issues which upset me on the original Horst site, and with the addition of a volume antenna, I believe the 'situation' has now radically changed.

I have now edited my original post, and do not think I 'should' involve myself in further discussion about the Horst.. Prior to the addition of a volume antenna, there was no problem, but now, with this addition (and also due to the fact that I have multi-dimensional outputs from both my pitch and volume antennas [i][pitch antenna allowing, amongst other things, duophony][/i].) I now feel there is potential for accusation of competetive conflict of interest.. the following may explain why..

My expierience (with Epsilon) leads me to believe that the pitch should be left as a single-function field if precision playing is called for, but that the 2nd function (in my case, the 2 dimensional pitch antenna consists of two equal lengths of antenna joined in the middle, and the sum of capacitance of the two controlls the pitch, while the difference between the two capacitances can be used for another function - including adding an offset voltage to a VCO to allow two VCO's to operate simultaneously - pitch difference a function of vertical hand movement) could be used usefully sometimes, or by a Thereminist who is really good! (in this mode,the respective volumes of the VCO's could be controlled by X or Y movement of the hand above the volume antenna - Or my E-Field Joystick, as I think it may be called - and the VCO's could be my Voltage Controlled "theremins" which are fully analogue heterodyning units - with full adjustment of octave span and tuning due to simply manipulating the CV's)

I expect to be in a position to announce modules which will allow construction of these instruments, in the next few weeks (certainly before the end of this year) and to have complete products on sale by Hands-off 2011 (last week July 2011) at the latest.

Fred.

Gordon wrote:

"The instant the movement of the volume hand of the player is reversed, however, and moves toward the pitch antenna..."

Should that read "toward the *volume* antenna"?

**********************

Quite right Gordon. VOLUME antenna

The damn thing only has two antennas - you'd think I could handle that!

I'm sure the new MIDI Wave theremin will be a boon to experimentalists and FX thereminists. I'm not sure how useful it will be to advanced precision players. The Ethervox has a nine and a half octave range, spread out over three registers - LOW, MIDDLE and HIGH - giving the instrument an even and consistent linearity regardless of tessitura.

One other advantage of the E'Vox is that because you can record the MIDI volume and pitchbend to a sequencer, you can make corrections simply by manipulating the data and then you can feed the recorded sequencer track back into the instrument (via MIDI IN) and the Vox will play it. Very hand for studio soundtrack work.

[i]"In PITCH SMART MODE, as the left hand pulls away from the volume antenna, the amplitude of the volume control MIDI signal increases, just as the volume increases in a standard, traditional theremin. The instant the movement of the volume hand of the player is reversed, however, and moves toward the // volume // antenna, in PITCH SMART a new MIDI "note on" message is sent with a "note on" velocity value equal to the last value displayed on the Ethervox performance screen." - Coalport[/i]

Interesting - and a bit surprising .. Does this mean that, when one wants to silence the Theremin in PITCH SMART mode, you *must* generate a MIDI note on message 'on the way' to silence? And how does one reduce the volume without triggerring a new note-on if movement towards the volume antenna triggers a note-on message? Am I being really stupid here? ;-)

I could understand if a note-on was triggered when the hand was moving away from the volume antenna after it had been moving towards the volume antenna (change of direction) - This is a way I thought about when looking into MIDI theremins.. And I thought it would be possible to extract 'velocity' data from the speed at which this change occurred - I never really saw volume / note-on data as the major problem - to me, the problem with MIDI from Theremins was the pitch (note number) / pitch bend / CC combinations and how to use these in a way that external MIDI equipment could cope with.

Anyway - I will be playing with an E-Vox again in a few weeks - and if I can fix it, will be able to try the PITCH SMART mode for myself.

BTW / OT : Does anyone have any technical data on the E-Vox? I really need schematics of the oscillators / front end - This particular E-Vox apparently has its field size collapse after a few minutes, but its pitch range stays constant !? I cannot begin to relate this behaviour to any 'normal' Theremin front-end.. Is the E-Vox a voltage generating Theremin like the 91's ?? I suppose I will find out soon enough with a 'scope.. but having some idea about it would be helpful! (or must I get back to LevNet and ask there? )-8

Fred.

It looks like horst has finally added a FAQ page that actually contains ANSWERS.

www.wave-theremin.com/faq.html (http://www.wave-theremin.com/faq.html)

Midi-IN would be nice to have – my guess is, it’s only a DIN-connector away. Why not ask him ?

BTW: I am not affiliated with this manufacturer BUT remember: Evil grows stronger because good man stay silent.

FredM asked: BTW / OT : Does anyone have any technical data on the E-Vox?

**************************

No.

I had been thinking of hiring someone to do a complete schematic (through reverse engineering) but it would have been very expensive and more importantly, it would have meant taking the instrument apart completely.

I sent our friend and colleague Thierry Frenkel some detailed photos of the insides of my E'Vox but I think the instrument was a little more complicated to understand than we had thought it would be. Perhaps Thierry could say more about this if he reads this message.

allo? allo! Thierry, es-tu la?

[i]"I sent our friend and colleague Thierry Frenkel some detailed photos of the insides of my E'Vox " - Coalport [/i]

Peter, If you still have copy of these photos, I would love to have them! I would also love to reverse-engineer to obtain schematics.. But not right now! - I suspect that if I got too involved in this, I might miss the HO 2011 deadline on what I should be doing!

The key, I think, will be determining its primary mode of operation - I had thought it might follow the E-Pro topology - the range switching in particular led me to this idea..

I now think it *likely* (due to the the 'fact'* that its field can collapse while its frequency span remains constant) that its front-end generates a voltage (or some other control element, be this current, voltage, PWM - whatever) and that the electronics maintains the 'span' of this data, and shifts (biases) it to the respective registers.. I strongly suspect voltage is the control medium -

And (on a personal level) this gives me strange feeling, because it is the method I have finally adopted for my Theremin products.. Am I once again going down a path pioneered by the great Bob Moog ? - And will I ever get out of his shadow?.. Its not too bad if I dont - It is a comfortable friendly shadow!

Fred.



*I have not seen this Theremin yet, and have learned that I cannot rely on client's description of problems they are having.. So my guesses are really premature. I am somewhat worried about the logistics of having this Theremin in my lab.. I simply do not have the space, so I really hope I can fix it in a few hours while the client waits.. but fear that this might be unrealistic.

BTW - and again, OT .. The ethical implications of one of my VCT (Voltage Controlled 'theremin') modules bothers me a bit - this is a VCT-EW.. It IS a complete standard Moog EM / EW Theremin, virtually unmodified (Equalizing coils and volume oscillator / front-end removed, and these replaced with a voltage controller circuit).. Is it ethical for me to copy Bob's circuit in this way? (it does sound far better than the 'normal' EW in the bass register, because the oscillators are prevented from going into lock and are forced to run with a difference frequency equal to the CV even when near to lock.. This gives the resulting 'distortion' without any 'stutter'.)

[i]"I had been thinking of hiring someone to do a complete schematic (through reverse engineering) but it would have been very expensive and more importantly, it would have meant taking the instrument apart completely. " - Coalport[/i]

Perhaps not.. Going over the complete instrument, and probing with a 'scope / meters / analysers, one could possibly deduce everything required without having to completely dissassemble the instrument..(if one does things strategically, and notes every waveform and reading, and where these are obtained, and takes a lot [hundreds?] of readings under differing conditions, and substitutes the antennas for controlled capacitances so that one does not get mislead by field effects).

With the above done,Duplicate sets of good quality photos (with test points and readings marked on these) would give most of what one needs to draft a schematic.. and one could return to the complete instrument to verify anything not clear on the 'photo's, and probe anything one left out in the original examination, to find any connections one cannot deduce.

IMO it is MUCH easier to 'reverse engineer' a 'live' circuit (or system) - One gets intimate understanding of the operation and 'blocks' which form the system - and in the majority of cases these 'blocks' will have a 'standard' topology.. There are only a few standard ways to configure oscillators / amplifiers / inverters etc.. determine the function of a 'block' and look at the components used by the 'block' and in most cases one can draw the aproximate schematic for the 'block' - one can then verify / modify this schematic by probing to verify that signals are what one expects.

Give me a 'dead' board, and it can take hours to even start at determining its function - let alone schematic.. But with a 'live' system, there is a real 'buzz' (no pun intended ;-) as one sees the pieces fall into place.

I would love to know how much you were quoted for this job! To be honest, I would find the task of giving a quote extremely difficult - if it was anything other than a Theremin, I would certainly charge no less than £2000 - But because its an E-Vox, would probably do the job for about £500. ;-) (actually, I would do it free if I was not able to extract money.. But my wife would probably murder me before I finished the job..)

Fred.

[i]BTW - and again, OT .. The ethical implications of one of my VCT (Voltage Controlled 'theremin') modules bothers me a bit - this is a VCT-EW.. It IS a complete standard Moog EM / EW Theremin, virtually unmodified (Equalizing coils and volume oscillator / front-end removed, and these replaced with a voltage controller circuit).. Is it ethical for me to copy Bob's circuit in this way? (it does sound far better than the 'normal' EW in the bass register, because the oscillators are prevented from going into lock and are forced to run with a difference frequency equal to the CV even when near to lock.. This gives the resulting 'distortion' without any 'stutter'.)[/i]

I don't know much about electronics so I can't make a judgement about how innovative is what you have done.

But if it makes the world better (and it does, if it makes a theremin sound better) my personal opinion is that the ethical thing is to release it. What would be unethical would be to have it under lock and key. It would be a pity that people were prevented from producing better musical instruments for being similar to existing ones, imagine how the world would be if that had happened with violins, pianos, guitars, etc.