The Pitch Field

Posted: 9/2/2009 6:38:07 AM

Joined: 8/31/2009


Firstly this is a great forum. I've be lurking for the last couple of weeks trying to glean as much information as I can about Theremins. Thanks to all involved for making such a quality resource.

I picked up my first theremin yesterday and spent a fun 3 hours last night trying to get some music out of it. It's a Burns B3 deluxe (thanks to Dan Burns for a great service and speedy delivery to Scotland).

Now come the dumb questions :)

As I understand it turning the pitch control alters the size of the pitch field so a larger pitch field will have larger spacing between note centers. I also understand that the note spacing is not uniform across the range. At both ends of the instruments range the note spacing progressively decreases as you move away from the center.

Does altering the pitch field size change the relative positions of the notes. i.e. does changing to a larger pitch field stretch and skew the field or is the resulting field simply a larger version of the same note mapping?

Following on from this do thereminists typically tune the same way for performing songs in different keys?

When playing a scale for instance do they use the same aerial fingering progression pattern but tune the theremin to change the key.

I feel I'm struggling to explain this... I'm a guitarist, suppose I am playing a melody and want to shift the key. I have two choices. I can put a capo on the instrument and play the same pattern higher up the neck (in a tighter form) or I can not use a capo and alter the scale pattern to play the melody in the original position.

So the 'brief' question is... Do thereminists ever use the pitch tuner in the same way that a guitarist would use a capo? Or do they prefer to try to tune the same way every time, keeping the note spacing consistent, and alter the pattern of their aerial fingering progressions as they move up the scale to play in different keys.

Thanks in advance
Sorry for being so wordy.
Posted: 9/2/2009 7:43:00 AM

From: UK

Joined: 4/15/2008

Hello Neeps,

Answers to some questions ...

It's sensible for anyone wanting to play the theremin to try, (at very least while learning), to keep things as consistant as possible. Therefore, it's good to adjust the pitch field in such a way that certain hand/finger movements always produce a fifth, third, tone, semitone or whatever. Because the note field can change due to external influences, it's hopeless if a certain hand movement produces a note jump of a fifth one day, then the same movement produces a fourth the next day; adaptability is great, but consistancy is useful for developing good muscle memory. To keep things consistant, most thereminists "tune" to a fixed interval ... usually, although not always, an octave, (by fixed interval I mean using a readily and consistantly reproducable hand/finger movement, and adjusting the pitch dial until the note-jump sounds correct for that particular "set" finger-shift.

Unlike a guitar, the same "aerial fingering progression pattern" for a scale will work no matter what the key - without any extra specific tuning. For example, for a basic scale you move through tone, tone, semitone, tone tone, tone, semitone. The finger positions you chose to achieve this pattern will work whatever note you start on ... and even works (in a way) for those who start "between" notes! Therefore, there is no need for a theremin player to "alter the pattern of their aerial fingering progressions as they move up the scale to play in different keys".

Tuning a theremin is rather different to tuning most other instruments. In a way, the theremin is always both in tune and out of tune ... and must be "tuned" to fit each individual player. By that I mean that while a violin tuned by one player remains in tune when handed to another player, a theremin perfectly tuned to suit my playing would likely be "out of tune" for you to play - until you adjusted the pitch dial to your personal specifics.

Posted: 9/2/2009 12:33:13 PM

Joined: 8/31/2009

Hi Thereminstrel thanks for your reply. I've been listening to your videos on youtube. Great stuff! You got me wanting a wavefront before I even had my hands on the B3.

I had read in the theremin buyers guide that the distance of lower octaves might be 10-20cm and the distance of a high octave might be only a few centimeters.

This is what made me think that two equal interval jumps would have different distances depending on the starting note. I imagined that if I played the same melody say half an octave higher that the hand/finger movements would need be all different!

From what you are telling me then there must be an area in the midde range where the octave distance is reasonably stable.

Tonight I'm going to try to take some measurements with the B3 and a tuner to get things right in my head.

Incidently, although I don't/didn't have much of an idea of the theory I was pleasently surprised that within a short space of time I was able to play recognisable melodies. Played extremely badly of course but recognisable all the same.
Posted: 9/2/2009 4:23:21 PM

From: UK

Joined: 4/15/2008

You're right to observe that playing something an octave higher or lower on a non-linear theremin (one with octaves of unequal sizes) would need some adaption on the part of the player. Not completely different hand/finger positions, but adapting those usually used. Speaking personally, I keep the same fingering movements but play at a steeper angle to compensate. It takes time, but after a while these compensations become second nature ... hopefully!

Also, it's my personal preference to, not only tune to a fixed interval, but always from the same note. This is because, as you've realised, depending on where in the field your hand is, the fixed interval jump can vary in size a little. Best, as you suggest, to pick somewhere in the fairly stable mid-range.

There are still several variables. Pitch can be affected by how close you stand to the theremin, its position in the room, the weather etc. also, remember that most people prefer to let their theremin "warm up" for several minutes before tuning, so that the field has "settled". You also have to be prepared to retune mid-practice from time to time. Nothing seems entirely constant ... although I guess this is what makes the theremin both a frustration and delight to play!
Posted: 9/4/2009 5:27:26 AM

Joined: 8/31/2009

I was thinking before in terms of a straight line from my position (center of chest) to the pitch aerial. I see now that by altering the angle of approach that this would alter the note distances.

Thanks for that :)

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