The ESPE01 module - first professional recording online

Thorwald Jørgensen has published a new video (audio recording with static pictures) on YouTube. He is playing Rachmaninoff's "Ne poy krasavitsa" on an Etherwave Standard which has the new ESPE01 module installed.

He doesn't play it in such a low register but this recording allows to hear that the mid and high register of the Etherwave remain unchanged by this modification.

Rachmaninoff's Ne poy krasavitsa played on theremin (http://www.youtube.com/watch?v=xWypljRBIGQ)

"but this recording allows to hear that the mid and high register of the Etherwave remain unchanged by this modification." - Thierry

Hey, Thierry... Unchanged?

I have never heard an EW sound so wonderful! To my ears, the (to me) unpleasant harshness has gone, whilst the 'brightness' is unaffected (as you know, I have always disliked something about the EW tone - but I have never been able to quantify what I disliked) - whatever it is, to my ears, you have fixed it! - Have you replaced the diode mixer or something like that?

Whatever - Congratulations!

Fred.

Thorwald's fine playing not withstanding, it doesn't sound like any standard Etherwave that I've ever heard before.

How is this possible? How can Fred and I be hearing things that others do not? Sure, it was an extrapolation when I surmised that the mod may have a positive effect on the higher ranges, but it seems it may in fact be true. The only thing missing, and what I've been asking for all along, is some hard, empirical evidence either way.

This recording may not be proof (since there is still no control of the variables i.e. microphones, amps, speakers, venues, settings, etc.), but it is evidence that it may be possible. What we are still lacking is a direct A/B comparison with one modded and one un-modded Etherwave, with the same timbre settings, recorded direct to the "board" (so to speak).

With all due respect to Thierry, while mathematics is a very good approximation of reality, it is not in fact reality. And after all...we're talking about *theremins* here!

Thierry did say that his first module did in fact (intentionally) improve the tone. It was Thorwald alone who requested a module that (allegedly) didn't change the tone in the upper registers.

@Fred: Thank you! You can't estimate what this positive feedback from you means to me!

@Jeff: I admit that I have no recordings with a direct A/B comparison which prove that the timbre remains unchanged as I told before. It's difficult to quantify because the Etherwave has no coherent timbre throughout the whole pitch range. There are "effects" due to the rather poor mixer design which start showing up (on the oscilloscope) already at the G above middle C and increase the lower you go. My mod eliminates most of these effects, so you hear naturally a different timbre below "middle G" but it's the Etherwave's natural timbre you had already before above it.

What does in effect add a bit more brilliance is my special way to tune the pitch circuits in order to extend the pitch range by somewhat more than an octave in the high register - a very sophisticated operation which takes me more than an hour. As a side effect the RF amplitude of the variable pitch oscillator varies somewhat more than usual through the pitch range which gives more brilliance in conjunction with the Etherwave's specific waveshaping circuit.

This extension of the high pitch range is not forcibly made in order to obtain "more tones" but it has the big advantage that the range which is normally the highest octave of the Etherwave will be not longer so close to the antenna and thus be less compressed which improves linearity. Both Carolina (she has an Etherwave Plus as a backup instrument) and Thorwald, and many others of my "clients" tell that it really improves linearity and playability and they won't miss that any more. As another side effect of this, Thorwald is able to play the Abalayeff's Nightingale as he does, up to the A almost 4 octaves above middle C.

So everybody who wants to have a best optimized Etherwave Standard or Plus should order it with the ESPE01 module included at Wilco Botermans' online shop and ask him to send it to me first for the "special" tuning.

What I also always do when beeing asked for tuning an Etherwave is adjusting the volume circuit accurately. As you can see on my youtube video where I demonstrate the ESPE01 module, the volume response of a well tuned E-Standard/Plus may be much better and more sophisticated than with the rather coarse factory settings.

Back to Thorwald's specific timbre: He has two Etherwaves, one with the mod and one without. In the higher register they sound similar. Thorwald has spent much time in order to find the settings of the waveform and brightness knobs which he considers now as the optimum and which he keeps now invariant. Due to component tolerances they aren't exactly the same on both instruments but it's always around "half past ten" on the waveform and "half past three" on the brightness knob. This signal goes then through a 10W tube amplifier. But all this doesn't yet make it. The most important factor is Thorwald's unique playing style and technique, because it does sound different and less interesting when I play on his setup with the same settings...

The E-Standard/Plus are not at all bad instruments. They have an immense potential and an excellent value for the money. Unfortunately most of those produced in the years after Bob's passing away don't seem to have been carefully and affectionately adjusted/tuned/optimized before leaving the factory which led to the actual reputation (bad linearity, muffled sound, limited pitch range, bad "on/off" volume response) although all this is avoidable with the actual circuit variant by investing some time, experience and lots of affection.

Thorwald was so kind to cut two recordings of the same piece together, so that on can compare the unmodified and the modified Etherwave. It is naturally not easy to compare since the "ancient" recording is from a practice session in the pianist's living room and the "new" one has been done under the same (and more professional) conditions as his recent Rachmaninoff recording (see above).

This youtube video is not intended for the "grand public" and has just been cut together for this discussion.

In addition Thorwald wrote me about the improved playability: "what I find amazing when I listen back is that you hear me strugle this piece on the old Theremin and I play without strugle on the new one!"

Here it is (http://www.youtube.com/watch?v=EZYiHNnqr2Q)

And for those who didn't hear the excellent bass demo with Saint-Saens' Elephants: Click here (http://dl.dropbox.com/u/1548721/ESPE01demoTJ.mp4)

[i]"it doesn't sound like any standard Etherwave that I've ever heard before.
How is this possible? How can Fred and I be hearing things that others do not?" - Jeff [/i]

Jeff - I wonder if the reason "others" dont hear what we do, is because whatever we hear on a standard EW doesnt bother them.. I suspect that peoples hearing and related neurology differs greatly - I love (in the 'right' context) sonic distortions which cause others to leave the room - and there are some sounds others like which irritate the hell out of me (Bose did some PA speakers many years ago, which became a loved standard - but I cannot listen to a performance where these speakers are used!)

My guess (and it is little more than that) is that, with the EW, there is an intermodulation distortion caused by the diode mixers changing capacitance - this distortion is extremely small, but (back when I was playing with the EW modification here on TW) I replaced this mixer with a true 4Q multiplier - this did get rid of whatever irritated me about the EW - but had knock-on effects due to the change in oscillator coupling (linearity etc) and I did not persue the matter as I had other things I felt were more important.. However, these experiments lead me to believe that either the mixer or oscillator interactions caused whatever it was I disliked.

The above is now IMHO academic - Thierry has implemented a superb (and by the looks of it, extremely simple) fix - I suspect that he has replaced the mixer in a way thich reduces oscillator coupling (or changes the frequency/coupling relationship) and this has the effect of increasing the playing range (particularly in the bass register, where the oscillators jittered between being in and out of lock).. I think it is fair to say that Thierry is the worlds expert on tuning the EW, and this expertise combined with replacing the mixer has solved all the problems.. I may, of course, be talking out my RS - but this is my best guess!


[i]" @Fred: Thank you! You can't estimate what this positive feedback from you means to me!" - Thierry [/i]

Dear Thierry, I am not easily impressed by what I hear (in fact, I am a downright critical b***ard at times ;-) But the sound of that modified EW blew my socks off! I have not been reading the threads about your module, this was the first I had followed.. I wish I was able to be at HO2011 to play with a modified EW myself, but this is now definately not possible.. I am sure your EW will be a crowd puller - good luck!

Fred.

I have just listened to the bass demo..

WOW!

I am now almost certain that something has been done relating to oscillator coupling! Bass was, IMO, where the EW sounded its worst..

Thanks Thierry - I havent had much interest in any of this stuff for months .. but I am almost curious enough to order one of your modules just to see what you have done ;-)

Fred.

ps.. I have just listened to Thorwald Jørgensen's other wonderful performances on u-tube.. I have absolutely no doubt - Yes, his playing is outstanding and I can suffer the 'raw' EW sound because of this - but the modified EW is just beautifull..

How can I describe the difference? The 'raw' EW sound is always less 'stable' - seems to have a scratchy harshness to it - reminds me a bit of the sound one gets from a poor quality D/A converter with clock jitter (I thought this might be some artifact from the u-tube processing, but its only there with unmodified EW recordings) .. It is most annoying to me, I can hear it so clearly - but cannot accurately describe it..

This annoying artifact (which is there at all pitches and at all volume levels on a raw EW) is removed entirely on the modified EW, but (to my ears) there is no difference in the tonal qualities between the modified and unmodified EW's apart from the removal of this (to my ears) unpleasant "something" in the unmodified EW.

If you do not hear this "something" you could not understand the effect it has on me - Although I say that there is no difference in the tonal qualities between the modified and unmodified EW's, this "something" is so annoying to me, that its removal actually makes the modified EW sound like a completely different instrument.. When I first heard the modified EW, I thought the harmonic spectrum of the instrument must have been changed - however, I now dont think it has.. Its just that I can now enjoy the 'pure' EW's sound without being distracted by this 'something'.

Hi Ruslan,
- I have been too embarassed to contact you, as I had made so many promises I was not able to keep.. Sorry. I am recovering slowly from the heart failure (am on meds which dilate the blood vessels feeding the heart, and feel a lot better for this) , but the underlying causes are still under investigation - I have had serious endocrine problems for at least 6 years which I did not know about - blood test results over these years show increasingly abnormal liver function, but these tests were ignored by my GP, and everything was blamed on diabetic control.. so I carried on, often feeling like shit, with my health getting worse, until my heart was unable to get enough oxegen (due to decreasing blood oxegen levels) and failed.. I am still anaemic, but at least my heart is able to pump sufficient blood to feed my hungry brain - LOL ;-).. I am going for more scans etc tomorrow, and suspect (hope?) that I will be admitted and they will get to the bottom of the problem.

WRT the EW tone - I suspect that Thierry's module does not actually (intentionally) alter the harmonic spectrum - but only he could confirm / refute this - and I suspect that the actual harmonics (leaving the matter of the "something" aside for now) are determined by the normal post-mixer EW waveshaping circuit - I suspect that, to obtain more control of the tone as you request, modification to this circuit would be required, and that this could not be implemented by Thierry's module.

What follows is pure speculation, and I only detail it because I know you are technically minded..

I suspect:
1.) Changes (improvement) in the bass register are the result of one or both of the following : A) Changes to the coupling between the ref and variable oscillators - on an unmodified EW these are crudely coupled via C2 and C6 - I suspect this has been changed. B) The diode mixer has been replaced / modified.

2.) The improvement in the tone (getting rid of the "something") is a consequence (possibly accidental) of whatever was done in (1) above..

Here is my postulation: Buffers have been inserted on the Hi-Z signals at C2 and C6, and a seperate coupling capacitor possibly connected between Q1:C and Q3:C. These buffers then drive the mixer.. The result of this would be that the changing capacitance of the mixer diode would not affect the oscillators, and that this removes the source of intermodulation distortion that has bothered me.

It may be ( I think it likely ) that a diode mixer is still used - replacing the diode mixer with some other method would result in a differently shaped waveform into U3, and it would be much more difficult to recreate the original EW tone if this was done.. [i] If the diode mixer has been retained, and Thierry impied as much, then this mixer will contribute distortion - however, whatever distortion it contributes does not bother me.. which is not to say that it wont bother someone else..;-) [/i]

Now - IF my above guesses are close, THEN the easiest way to obtain an Enkelaar type tone would be to buy a SC (Jaycar) theremin kit, and only fit the mixer and audio components, and do the related Enkelaar modifications http://www.element14.com/community/docs/DOC-23047/l/enkelaar-theremin-schematic

You will need to fiddle with coupling components and power supplies etc, but you should be able to couple the buffered variable and reference oscillator signals from the EW into the Enkelaar mixer, and have a seperate "Enkelaar" audio output..

However, the above is NOT something I would want to do to a brand new EW+ which has Thierry's module fitted, and which has been painstakingly tuned by Thierry! - I think you may find it better / easier to put a parametric EQ on the audio output - or even a VCF driven from the CV output.. the Enkelaar waveform is (apart from its "wasp in a jar" setting) a lot more sinuosoidal than the EW, so rolling off the higher harmonics might be enough to apro