Preview Harmonic content - Advice wanted.

I am getting down to the (hopefully) last bits for my Theremin.. and have a question..

I have noticed when playing with loud background music, and the Theremin set to produce low harmonic content, that (to me) pitch preview needs to be turned up really high in order to hear it.. This is particularly true for bass notes if they are quite sine-like, but also applies to higher pitches which are often more sine-like.

My (like all other Theremins I have seen) Theremin taps the audio before the VCA, and uses this to feed the pitch preview.. so the preview sound is exactly what will be played when one lifts the volume hand (apart from the fact that I find it difficult to co-ordinate both hands - so generally only manage to stay on-key when not using volume.. but I have confirmed that this is my playing, and not my instrument, which is at fault).

I have been messing about with the preview circuitry, and now have a seperate crude square wave which can be mixed with the 'normal' preview signal.. The extra harmonics make the pitch discernable at much lower volume level to the headphones..

So - My questions are these:

Does anyone else have the problem with pitch preview that I mention above?

Would adding a tone control to allow adding harmonics to the preview signal be a worthwhile addition?

The cost of this addition would probably add about $5 to the price, and would add another knob.. I am inclined to include it - I certainly find it essential for my playing -

Interesting question. Here are my first thoughts. Hopefully any errors in my thinking will prompt someone more knowledgeable to correct them. :-)

There are two issues at work - the ability to distinguish the preview from other sounds and the ability to determine the pitch of the preview in relation to a reference tone (i.e. what is being played by other orchestra/band members at the time.)

I am sure there are research papers on both topics, but my solution to hearing the preview clearly would not involve messing with the timbre. Rather I would consider feeding the preview to noise cancelling or damping headphones and leaving one ear uncovered to hear the band playing.

It also occurs to me that when someone wants to make an announcement to a noisy audience (say at a wedding reception) they will tap repeatedly on a glass with a spoon. It is not loud, but it cuts through the hubbub. Perhaps there is something to modulating the volume with a low frequency sawtooth. (Say 2 or 3 Hz?)

This may also relate to the second issue. At the theremin workshop we attended in Oxford, when a person was having trouble finding the right pitch, rather than pressing the sustain pedal on the piano, Lydia K tapped the relevant key repeatedly.

By contrast, at the workshop I attended in Lippstadt, Barbara B was providing a reference tone from a small hand-held synthesizer, using a waveform that was very rich in harmonics. (No, not a stylophone - a slightly more pleasant sound, but not [i]that[/i] far removed.) While it was certainly easy to hear her little synth it seemed to cause problems for a couple of the students, who were playing a different but harmonically related note in response to the reference tone, as if they were locking on to one of the partials rather than the fundamental.

It occurred to me at the time that tuning forks are pretty much sine wave generators, so perhaps best for identifying pitch. But then again pitch-pipes have a lot of harmonics. (At least, the ones here (http://www.harmonize.com/metropolis/online_pitch_pipe.htm) do, according to the sonogram I just made of A.)

Oh, I don't know. Perhaps best to hear from someone who actually uses pitch preview and reference tones. What do people prefer, tuning forks or pitch pipes?

Personally, I believe, for those who would use a pitch preview, an adjustable timbre would be helpful. For others, it would seem to be an un-necessary expense.

Being someone who suffers from impaired hearing, playing the theremin is more of a challenge; if it wasn't hard enough already.

However, I feel my affliction brings many of these issues into sharper focus.

You are absolutely correct saying the pitch of a sine wave is much more difficult to determine (at least for me). Adding other sounds or noise to the mix substantially increases the difficulty.

Thus, I prefer playing timbres with richer harmonic content that others might find annoying. I also seem to prefer playing in the high end of the range, but people without my particular deficiencies may not find that to be an advantage.

I've found that the ability to adjust timbre is important when playing along with other instruments. This provides some ability to sonically separate my theremin tone from the rest of the mix.

When trying to play along with another theremin, I had great difficulty hearing what I was playing...unless I was playing out of tune! Obviously, this proved to be an act of futility.

The thing that helped me the most was when I was playing along with a piano-playing friend. The sound was run through a mixer and we listened through headphones. This allowed my theremin to be panned and sonically separated inside of my head. Without the headphones, I had difficulty separating my theremin sound from that of the piano.

Granted, most people with average hearing will probably not have some, if any, of these issues. But they do illustrate potential problems whether one is aware of them or not. So, perhaps they will be of some help.

I favor a pitch-preview timbre that is foundational. As one goes up the overtone series, the overtones become so closely spaced (in pitch) that one can't tell if the note is in tune. It is important to tune to the fundamental rather than the overtones.

I just make sure that my preview amplifier's level is set such that I can hear the preview without clipping and choose an earbud that has good bass/tenor response.

I'm finding this interesting. I'm not sure my comments will be much use as I don't use pitch-preview. However, maybe one of the reasons I don't use it will be of interest.

My only theremin that has a pitch-preview facility is the Wavefront. When I've tried it, my problem hasn't been differentiating the sound of the theremin from other music (CD backing tracks, either piano or orchestral) but differentiating the sound I hear through earbud/earphones from the externally audible sound of the theremin. Because the two sounds (one heard by each ear) are identical in tone, there's a point with the volume where I'm not sure whether the external sound is audible yet or not. (Sorry ... it's hard to explain clearly). I've tried the preview volume at different settings, but there's always a point where both are so similar I'm not sure whether I'm audible yet to the invisible "audience". Therefore, I suspect that a pitch-preview that can be tonally different would fix this. Pitchwise, both would be identical, but I'd be able to tell which was which, and adjust/play accordingly.

Like Jeff S, I have impaired hearing, (also I have tinnitus ... hearing a loud whistling/ringing in my ears all the time anyway, just to make playing the theremin even harder!!!) Like Jeff, I find it easier to "hear" the theremin when I play in higher octaves - and sharper tones seem easier to grasp.

There are other reasons I've avoided pitch-preview, although I guess these aren't so relevant. While I fully accept it's a "must" if playing with an orchestra or other musicians (and you need to "come in" without pitch-fishing), as that's never going to happen, and 99% of my playing time I'm alone, then previewing the note is of little use to me. I also believe that, in the primary stages of learning this instrument, it's better to develop good (or as good as possible) intuitive playing, rather than relying on a "safety-net". I'm not one of those who see pitch-preview as cheating, but neither do I see it as a useful learning tool; it's not like using stabilizers on a bicycle until you get your balance. Rather, I see it as something valuable for players who've reached a reasonably professional level and may want to perform in public and, understandably, prefer to ensure there performance is the best it can be.

Finally, the other reason I don't use pitch-preview is that, (perhaps unnecessarily), I have safety issues! The first and only time I used an ear bud (borrowed from an i-Pod), the bud got very, VERY hot within a minute or so, to the point of burning my ear. (It also wrecked the bud so that I got next to zero volume out of it via the i-Pod afterwards). I've been afraid to use an earbud again in case of damage to the ear. (Any suggestions re safe ear buds would be appreciated). Standard "can" earphones seem fine - but in the unlikely event of me playing in public wearing phones over one ear isn't a look I'd like to go for!

Anyway, in short, a pitch-preview with a different tone might work for me, and may tempt me to try preview again! Good idea.

[i]I also believe that, in the primary stages of learning this instrument, it's better to develop good (or as good as possible) intuitive playing, rather than relying on a "safety-net".[/i]

My experience has been the opposite -- the use of a pitch-preview assures that one acquires solid hand/ear coordination from the first stages of learning. After hours of careful playing with a pitch-preview, my non-pitch preview technique is solid because my muscle memory is ingrained.

I believe that muscle memory and hand/ear coordination are indispensable for accurate theremin playing. I distinguish between intuition and technique and, as such, don't consider intuition to be useful as a technique.

A pitch preview does not provide a safety net. It merely allows one to fish in the privacy of one's earbud rather than to fish publically from a speaker.

Pitch-preview or not, there is no safety-net when playing the theremin! :)

My two cents:

If the background is loud enough one may discreetly fish for pitch without pitch preview (even Lydia does so). Pitch preview is mostly needed when there is just not enough background noise. And in this situation you'll be able to hear it.

Thank you all - Quite a lot to think about here! ;-) Alas, like everything about the Theremin, a simple question results in deep issues coming to light.. I am left having to choose between 'crafting' a 'solution' carefully, or going for the quickest simplest 'fix' I can find.. By nature I do the most difficult solution I can find.. :-(

[b]1: Preview - Hearing preview, and the problem of 'locking' to wrong harmonics ..[/b]

It seems I am not alone in wanting / requiring a harmonically rich preview sound..

[i]“Thus, I prefer playing timbres with richer harmonic content that others might find annoying.” - Jeff S

“I've found that the ability to adjust timbre is important when playing along with other instruments. This provides some ability to sonically separate my theremin tone from the rest of the mix”.– Jeff S[/i]

It also seems I am not alone with a problem (I just put it down to my natural tendency to improvise, causing me to shift to harmonic intervals - LOL) of picking the wrong harmonic..

[i]“While it was certainly easy to hear her little synth it seemed to cause problems for a couple of the students, who were playing a different but harmonically related note in response to the reference tone, as if they were locking on to one of the partials rather than the fundamental.” – Gordon C

“I favor a pitch-preview timbre that is foundational. As one goes up the overtone series, the overtones become so closely spaced (in pitch) that one can't tell if the note is in tune. It is important to tune to the fundamental rather than the overtones.” – kkissinger[/i]

Perhaps having a preview sound which consisted only of octave related (power of 2) harmonics would solve the above problem.. ('raw' signal with extra 2nd,4th,8th,16th and perhaps 32nd harmonics added)- is this what you mean by "foundational" Kevin?
I think the above would solve the problem (one may play an octave higher, but you wont play a third or fifth interval) - But it is a much more complex bit of circuitry to implement.

[b]2. The problem of differentiating preview from actual Theremin output .. [/b]

[i]“my problem hasn't been differentiating the sound of the theremin from other music (CD backing tracks, either piano or orchestral) but differentiating the sound I hear through earbud/earphones from the externally audible sound of the theremin.” - Thereminstrel [/i]

I have also had this difficulty - and found that higher harmonic content from the preview signal seems to help..

Perhaps I should explain my present setup - and what I am actually doing..

At present, all the audio signals (preview, square-wave preview, Theremin output, music I am trying to play along with) are seperately fed to a small mixer (Mackie 1202).. and the output from this goes to my amp and drives my headphones.. I cannot play through my speakers because it would lead to a divorce .. :-(

I am playing along to a wide range of different 'backing' music - the (primary) idea being to tailor the available sounds from the Theremin to cover as wide a range of genre as possible.. So I think that this might be close to a "worst case" situation for testing preview - Probably having one earbud which has only preview signal, and excludes other sounds, would be easier - I will test this by panning the preview to one ear next time.

Thanks again, everyone!




ps.. A seperate question..

I am thinking about building my mixer setup (described above) into the Theremin - having a stereo line level input, and being able to mix this with preview and Theremin output to drive the headphones.. This would give a self-contained system for practicing etc (just plug an MP3 player or whatever into the Theremin)
?

FredM >>>
My answer to your "seperate question" ...
Anything that makes the theremin more playable seems worthwhile including even if it means a slight increase in cost. However, non-essentials that increase cost would, in my opinion, be best avoided.
I, too, often have to practice in a way that's inaudible to others, and often want some backing track playing. I simply wear can-earphones from the amp or directly from the theremin, and have an i-Pod MP3 player in my pocket with a single earbud in one ear usually tucked beneath the left earphone can. This works fine for me - especially as I can adjust the volume of each seperately.

kkissinger >>>
Thanks for your reply; I always appreciate your thoughtful input here. I was very sleepy when I posted my comment, and my brain wouldn't find the words I was looking for. "Intuitive playing" and "safety-net" were the nearest I could manage, and didn't really convey what I was thinking, so perhaps you misunderstand me a little. I'll try to explain.

By intuition, I didn't mean "winging it" or guessing where notes are. I fully agree that a solid technique is vital. However, I find that if ever I slip into thinking/calculating where a note might be, then I inevitably miss it - whereas if I simply "flick" to it without thinking I'm MUCH more likely to hit it. This is what I meant - but I don't think "intuitive playing" was the right descriptive phrase; I guess it's actually relying on well entrenched muscle-memory (whether developed with or without pitch-preview). When I have tried pitch-preview, I seem more likely to slip into thinking/reaching for a note, rather than just going for it with a flick of the fingers/hand ... and to my mind, at this stage in my learning, this is something I'd like to keep improving. Strangely, PP seems to make me a less confident player - which I know is the opposite for most people. Maybe practicing with PP I'd get through it.

The thing I really can't understand from your comment is this:
Quote: "The use of a pitch-preview assures that one acquires solid hand/ear coordination from the first stages of learning. After hours of careful playing with a pitch-preview, my non-pitch preview technique is solid because my muscle memory is ingrained."

Why would use of pitch-preview give a player a more solid hand/ear coordination and better ingrained muscle-memory than non PP practice? Surely all pitch-preview does is allow you to hear a note "in private" as you say. What's different about this and practicing in a room alone (without PP) or practicing while wearing earphones? Surely such practice would still allow a player to adjust hand/finger positions in response to hearing the note, and thus develop muscle-memory in the process. Why would hearing a constant tone through an earbud make that a more efficient way to develop hand/ear coordination? Wouldn't "hours of careful playing" WITHOUT pitch-preview also result in a "technique that's solid because muscle memory is ingrained"?

Please don't think these questions rude or challenging ... I'm just rather puzzled and would appreciate any clarification!

I guess with this odd instrument, in the absence of standard tuition, players have to find what works in their own circumstances (hearing problems being one). I don't rule out ever using PP - and would like to get to grips with it sometime perhaps - but for me personally, during the early stages of learning, listening to a constant tone at the same time as listening to what I was playing while trying to stand perfectly still and make both hands do the right things seperately from each other, would've felt like an overload. I felt I needed to develop muscle-memory first, without what would've seemed (to me) like an extra distraction I wasn't ready for.

LATER ...
After some reflection ... I think perhaps I may be misunderstanding you. Perhaps you weren't saying that using PP was a more efficient and effectiv

Thereminstrel: A bit like the centipede's dilemma?

http://en.wikipedia.org/wiki/Centipede's_dilemma