Subscope Theremin

My beef with the Pegna is: Why have it for sale out there on the www when you cannot even fulfill the orders in the first place? Certainly not a good way to build a positive reputation for yourself or the product.

I agree, setting up a webpage should probably be the last step of going into business.

"Why have it for sale out there on the www when you cannot even fulfill the orders in the first place?" - Amey

"I agree, setting up a webpage should probably be the last step of going into business." - Chobbs.

I agree with you both - But I do understand why/how an ambitious eccentric creator can foolishly promote a product they honestly intend to produce, have web sites etc, but then get distracted or whatever.. Not too sure about "the last step" - A web site can be a great way to "test the market" at the early stage of (or even before starting) a business - Provided one doesnt tell lies or deliberately mislead..

The mistake, IMO, is not in having a web page or "promoting" your product.. The mistake is in not clearly disclosing  such "problems" immediately that they occur.

If the Penga site said "I cannot produce these theremins on demand, I may not be making any more.. But if you want to be put on a list, I will contact you when / if I can produce a theremin for you.." I think all the potential sources of trouble and ill feeling would evaporate.

As I say - I do understand how someone gets themselves trapped by expectations they have generated, which they had every intention of meeting, but the universe had other plans... And I do understand the "beef" from those who feel let down..

And IMO its all needless - If Mr Penga played "open hand" the pressure would be off him,  potential future customers would not be put off buying his product if / when they got into production... Or at least I certainly hope this is the case... ;-)

Fred

"I just got a Subscope theremin with pitch preview a few months ago and I LOVE IT. ...The linearity is beautiful. The pitch preview is a godsend and adjustable to your preferences as to when you hear it (the closer you get to the volume antenna the louder it gets- the exact opposite of the regular volume) and how loud it is and when it drops out..."  - All Souls Night

Very interesting way to handle pitch preview, I figured it was always (for all Theremins that have this feature) just a constant volume droning away in the earphone.  (Kind of wonder if/when someone will Bluetooth this?)

ASN, does the Subscope pitch cramp up near the antenna?  Is the controls layout of your Subscope similar to Amethyste's?  Could you (and/or Amethyste, and/or Chobbs) give us an explanation of what each of those controls does?  TIA!

"Very interesting way to handle pitch preview, I figured it was always (for all Theremins that have this feature) just a constant volume droning away in the earphone.  (Kind of wonder if/when someone will Bluetooth this?)" - Dewster

Yes, it is an interesting feature, and I am surprised that it works! - To me (with my extremely limited use of the volume antenna, so I am really in no position to pass any judgments ;-) I would think it would be extremely distracting..

I have my preview at a constant (adjustable) extremely low level.. I use stereo cans with a sub-mixer and mix the theremins main (after VCA) signal back to the cans with preview set just loud enough that I can use it when the volume hand is muting the theremin..

The whole player monitoring side is something I spent a lot of time on - and IMO, if the cue (preview) level is low and constant, then the theremins "main" output takes over anyway when its volume is raised - no need to reduce the cue.. To me, having a constant cue level allows me to judge when the signal I am hearing is getting louder because its being passed through the VCA.. If the cue drops off as the post-VCA signal increases, how does one know whats coming from the cue, and whats actually being output?

I also think that the tone of the cue signal is probably quite important - needs to be either a sine or a waveform containing a clear identification of the fundamental.. A complex waveform at low level can, I believe, convey a "wrong" pitch cue - To me, a sine wave with a constant (flat) audio level over the whole playable spectrum (as in, no filter - or equalized so that the player hears 20Hz at the same loudness as 4kHz) is best .. You only really need cue when the theremins voice is muted or below the cue level - once the theremins loudness is increased above the cue level, you want to listen to that - but the sine fundamental from the cue mixes with the richer harmonics from the theremin waveform, and if designed so that these are in phase, gives IMO better 'focus' on the theremins true pitch even when you dont "need" the cue signal. 

Bluetooth is a good idea - and cost is reducing (for the TX end) - one can now get low cost modules or "shields" (oh, I do hate the Arduino terminology!).. But, even though quite low cost, they are too high I think to add as standard to low-mid priced theremins..

And there is a quite simple external solution - One can buy cheap battery powered FM transmitters designed to be plugged into the output from small MP3 players etc - And cheap FM radio headphones / earbuds are available.. TX plugged into theremins preview output and for about £20 all in, you have wireless preview..

Fred.

I agree that the waveform in the pitch preview is important for a clear pitch determination. You would think that a sine wave would be perfect because of it's pureness, but unfortunately our ears does some really strange things when confronted with sine waves... For instance a sine wave at a constant frequency can be perceived as having a different pitch if you change the amplitude. Listening tests have confirmed that a 150 Hz sine wave with an amplitude at 45 dB will drop around 12% in perceived pitch if we change the amplitude to 90 dB (Sundberg: The Science of Musical Sounds). I personally hear a semi-tone pitch difference. The shift in perceived pitch is also frequency dependent and if we take the Fletcher-Munson Curves into consideration this becomes a complex issue. Here's a demonstration I did in Pd (listen in head phones for best results):

The solution is to use a complex waveform where the pitch shift is not perceived.

" Listening tests have confirmed that a 150 Hz sine wave with an amplitude at 45 dB will drop around 12% in perceived pitch if we change the amplitude to 90 dB (Sundberg: The Science of Musical Sounds)." - Jesper

Fascinating observation - My copy of "Science of musical sounds" is probably a bit older.. Miller, 1922 ;-) .. One of my favorite books I have owned for 40 years, bought from my technical college for 20c when they cleared out old books.. So I got a bit excited when I saw reference to "it" - but

But doesnt the above just confirm, from a perspective of preview, that the preview amplitude should not vary.. that it should be a constant low level ? As I see it, a sine wave held at a constant amplitude should be percieved as a constant frequency - and 45db is probably as loud or louder than preview ever needs to be.

As for complex waveforms, I think one can use some waveforms without problem, but others can be misleading.. I have not explored the science behind my experiments, but, to me, sine is best - followed by waveforms based on filtered ramp (as in, both even and odd harmonics, but with the harmonics being attenuated quite heavily - a ramp into a tracking filter with 12db/octave roll-off for example) .. Alas, such complexity comes with a higher than acceptable price tag.

I REALLY dont like preview based on an odd-harmonics-only type waveform (square / triangle) - sad, because these are the easiest to produce..

But all the above may just be a matter of personal taste (or personal ears) anyway.. The worlds most popular theremin is one that I have real difficulty enjoying - I really dont like its sound (or some quality of its sound) regardless of how its controls are set.. Most people however are perfectly happy with this theremin -

Fred. 

I have just listened to the example in your last posting.. I cannot hear any change in pitch!  LOL ;-) ... Not saying I dont believe the theory or whatever - just saying that, to me, each tone sounds exactly the same as the last, no matter what I do or how loud or soft I crank the levels on the cans.

@ Fred:  I'm guessing the theremin you don't like is the Etherwave...Have you ever played around with one which has Thierry's ESPE01 mod?  I also didn't like any of the tones on my unmodified Etherwave plus, but I do like ONE setting on my modified instrument....I don't know how, but I do know that this mod improved the tone...(at least to my ears)...

Also, is the tone on the pitch preview independent of the tone one has set on the instrument, or does this depend on the maker?  I know that there is a simple jumper mod that can be done on my Etherwave plus to turn the headphone output into a pitch preview, but I have hesitated to do this up until now because I am sometimes all thumbs and it would kill me if I damaged my instrument while trying to work on it....and if the pitch preview has the angry bees tonality, it would be worse than having no preview at all, in my opinion....

Pitch preview depends on the maker. In the Etherwave Plus, the pitch preview's sound is independent from the Waveform and Brightness settings. It is the raw audio signal behind the mixer.

"I'm guessing the theremin you don't like is the Etherwave...Have you ever played around with one which has Thierry's ESPE01 mod?  I also didn't like any of the tones on my unmodified Etherwave plus, but I do like ONE setting on my modified instrument....I don't know how, but I do know that this mod improved the tone...(at least to my ears)..." -Mollydad

Yes, it is the EW I am talking about.. But I dont really have any "right" to talk about it - I have only played with a real EW a few times at Lydia's get-togethers, where exploring the tone possibilities hasnt been possible - But I have not played an EW that I like - I dont like its tone, and I dont like its response / linearity.. And I know this must be some "personal" thing, because technically the EW is far superior to some other theremins I get on with.

Everything else that has come from Moog has (to me) been a pleasure to play, and sounded wonderful - I certainly dont have any inclination or bias against Moog products! But the EW (and to a lesser extent the EW Pro) are not instruments I get on with - And mostly I have absolutely no idea why this is.

Most of my "EW" expierience has been with "EW clones" I have built for evaluation.. As for "Have you ever played around with one which has Thierry's ESPE01 mod? " the answer is no.. My understanding (and it may be wrong) is that Thierry's module consists of a buffer for each HF oscillator, feeding a duplicate of the diode mixer in the EW - That the only influence this has is to decouple the oscillators and provide a lower impedence drive to the mixer.. What I dont know is whether the mixer has been changed in any way - but I have asssumed it has not been changed.

I have played with experimental EW "clones" on which I buffered the oscillators prior to mixing, and this does (IMO) improve the bass response (I believe the "problem" at the bass end of the EW is due to oscillator syncronisation - I think the oscillators pull too abruptly, and one gets a stuttering effect as their frequencies get close - but this is just guessing... Eliminating (or reducing) this coupling by buffering the oscillators eliminates this 'problem'.

I suspect that it is the deliberate distortion mechanism acting on the diode mixers output waveform which produces the tonal quality I dont like.. I am not particularly fond of the sound from diode mixers, and I dont like the sound from an over-driven / "unbalanced" OTA much.. Oh, there are some exceptions - but whatever, and for whatever reason, there "is" a quality about the sound of the EW audio stage that I PERSONALLY dont like much.. But I must emphasise the "Personally" - My analysis of the waveforms shows me no clear reason - as in no obviously unpleasant harmonics - to "justify" this dislike.....

Its not only the EW which sometimes falls foul of my tastes.. I have built mixers which produce what should  (from analysis of the spectrum) sound great, but which dont please me.. and some I do like probably will be disliked by other ears.

The above is one reason why I like to go for a multi-path audio stage - And dont like to feed all the audio through a common distorter, because, if one does that, then one cannot escape the coloration this distorter applies to every signal.. so if you dont like it, you cant bypass it.

With regard to preview - It seems to me that most theremin manufacturers just tap the existing pre-VCA audio (The fact that preview has been a focus on the Subscope is, I think, quite unusual) . With an unmodified EW, this is probably the only place one can get the signal.. But if the EW has a buffer module, I would take the buffered oscillator signals into a seperate mixer built using a true multiplier IC (MC1496 or AD633) to produce a sine or more sine-like output waveform for preview.. I would also add the ability to mix this sine into the main pre-VCA signal - a seperate additional tone control.

(the above is one of the really nice things about buffering the oscillators - you can take the buffered signals into whatever mixer you want - so you can have a diode mixer, a 4QM mixer, a FET mixer all driven simultaneously and producing their charactaristic waveforms, and then mix these to taste! - sadly, [IMO] the EW combines the waveshaping/distortion in its LM13700 VCA, so you need to add another VCA if you want to bypass its coloration )

Fred.