Pitch Distortions

I play theremin in a band, but when things get too loud the pitch distorts so bad that it's basically un-playable. Someone suggested that i get a different amp, but i really don't think that's the problem. anyone have any suggestions?

Kyle

Kyle,

Welcome to Thereminworld. You will find lots of knowledgeable folks here.

In considering an answer to your question, a number of factors come into play.

The ear simply is less sensitive to gradations of pitch at loud volume. If all seems ok when playing loud but later sounds out of tune on a recording of the performance (listened to at a lower volume level) then the music may be loud enough that your ear can't discern pitches during the performance.

As you know, in this day and age many bands play at dangerously high sound levels. To invest in a decibel meter (Radio Shack sells a decent one) would be a good way to keep the levels from creeping up and damaging your or your audience's ears.

Ok, assuming that you are at a safe level, the ear still is less sensitive to gradations of pitch as the music gets louder. This is simply "mother nature" at work.

Lately, there has been a spirited discussion thread on Levnet about the best sound setup for a Theremin. Among suggestions are that the performer use a pitch preview and that the Theremin should be in its own channel/amp/speaker -- the speaker placed behind the thereminist. No other tracks should be mixed with the Theremin output.

The issue is not settled though -- many Thereminists run their Theremins into the PA and mix it in with everything else.

You may want to identify which Thereminist(s) play closest to the style that you wish to emulate and ask them what sound setup they use or would recommend.

As far as the pitch actually "distorting" as you play louder.. a properly adjusted Theremin should hold a steady pitch regardless of the volume.

Again, I am assuming you are speaking of the volume of your PA rather than the volume of the Theremin's signal.

Good luck and keep us posted.

i don't know if i made it clear, but it's not that i'm playing the theremin too loud, the sound only distorts when other instruments play loudly (mainly the bass and drums). i guess the real question is can powerful sound waves, like the ones produced by bass or guitar amps or kick drums, distort a theremin's sound?

What determines the pitch of the Theremin is the distance between the pitch antenna and a source of capacitance (i.e., your body). Sound waves themselves don't contain any electrical property that would modify the control zone.

However, the vibrations themselves could shake the pitch antenna and/or wire leads within your Theremin and cause pitch fluctuations. If your Theremin is mounted on a mike stand the mike stand may be picking up resonances from the floor, too.

The solution would be to try to isolate your Theremin from the source of the vibrations.
Try putting a heavy towel over the case of your Theremin and set your stand on a pad of some kind, start jamming away with the band, and see if the pitch fluctuations are less than before.

Good luck!

grea ideas! i never even thought of that. it's a theremax, so it could be the case that the wires inside are shaking. thanks for the tip. i will let you know if it works

Kyle

Kyle,

The internal leads, both the antenna leads and the flying leads from the control panel are subject to interference and vibration.

When I first built my Theremax, I gathered up the flying leads and bundled them with wire ties in an attempt to make it look neater.

Problem was, the signals bled from one lead to another and caused distortion. So, my leads now are unbundled and spaced as far apart as possible.

When the pitch antenna shakes, it really imparts a lot of vibrato to the signal. If you are using the stock antenna, it takes very little to shake it.

So, I suspect we are on the right track here... suspecting physical vibrations rather than electrical interference.

Some folks stick tennis balls or other objects on their Tmax pitch antenna to protect their eyes and perhaps you need something their to dampen the vibrations. I would suspect your pitch antenna is the culprit...

I am still running my Tmax with the stock antennae however will replace them with better ones soon.

I use a Barbie doll head on mine.

I almost poked my eye out one night breaking down my equipment.

so you don't think it has to do with the leads coming from the circuit board to the antenna? because it's not that the pitch moves or anything...it sounds like it's being run through a distortion pedal or something

Well, I'd check the pitch antenna first, then the interior leads.

Since the vibrations would match the frequencies of the pitches causing the vibration, the resulting FM would sound like intermodulation distortion (IM distortion).

ahh, yes...because the distortions are mainly a problem around the pitch i'm trying to get (which is often the same pitch as the bass or guitar)