Theremin Volume Control - What's Ideal?

Posted: 8/21/2016 9:54:48 PM
Valery

From: Russia, Saint-Petersburg

Joined: 6/6/2016

Yes, Christopher. I think the shipment is expensive, so I offered to offset the costs. Urs Gaudi sent for me Open Theremin in the envelope 15 x 20 cm. Thickness of about 1 cm. shipment took 2 weeks. The option of shipment of schema components for later Assembly is acceptable. Possible option: I have a friend in America who often travels to St. Petersburg. Is going to come after Christmas. I can ask her to bring the parcel if it will not be difficult.
(Internet browser Google Chrome Has built in translation function, so you can write in your language, the more that I half understand without an interpreter. ;) )
Posted: 8/22/2016 11:42:07 AM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Valery the lady after Christmas is a great idea, I want to send you many parts as your success is my success.

---

Everyone the photo below is my pulse width modulation theremin volume control. Now that I can do multi layer printed circuit boards someday I will reduce the size of the 3” x 8” board. Right now I have about 30 of these longer boards waiting for that adventurous University student to experiment with. This same board can also be the Pitch side for sound with a variation in the components.

The standard passive theremin volume can use over 2 kHz in variation or off tuning to quiet the sound. My PWM approach can do the same thing in 200 Hz that can be spread out over a 24” volume-shading window using a 4” antenna. Use the 4” high voltage wire, I showed earlier in this thread, placed in the loop and the volume can have a softer response on the outside edge of the loop, then aggressive at inside edge near the wood box. The parts are minimum and the Vactrol can be seen.

I hope I am not falling into that pit of moving away from practical and making something so complicated it gives me an excuse for not succeeding.

Christopher

 

Steve Jobs

“Simple can be harder than complex: You have to work hard to get your thinking clean to make it simple. But it’s worth it in the end because once you get there, you can move mountains.”

 

― Steve Jobs

 

Posted: 8/22/2016 8:01:21 PM
ILYA

From: Theremin Motherland

Joined: 11/13/2005

"But that's a side effect, no?  Ideally the oscillator frequency wouldn't be influenced by the antenna LC, correct?" - dewster

yes, and divider of C14-C15 helps to neutralize this influenceBut there is nothing wrong in this effect, the circuit is operable in any case.

 

 

 

 

Posted: 8/25/2016 6:46:58 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

August 28, 2016 - Happy Birthday again Lev Sergeyevich Termen.

Here is a sound sample of my theremin volume method using Pulse Width Modulation. I find it to be more precise than the passive approach. It gives good control throughout a 40 cm volume window with the quiet range spread out for easy soft control. It is distortion and noise free at any level.

Ideal Volume Control .wav

It is best played in Audacity so you have a visual. I am using a radio for the audio.

Christopher

Posted: 8/25/2016 8:37:44 PM
Valery

From: Russia, Saint-Petersburg

Joined: 6/6/2016

Hi, Christopher! Right hand controls pitch, the left hand controls the nuances of volume, rather than to modulate the audio? The footswitch?

Posted: 8/25/2016 10:17:38 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

 

The right hand controls the pitch, Yes

Left hand controls the loudness or amplitude of the acoustic signal.

Without pedal

Christopher

Posted: 8/26/2016 9:13:23 AM
Valery

From: Russia, Saint-Petersburg

Joined: 6/6/2016

 

Oh, I know. The volume level changes smoothly enough and at large and at small values. The impression is pleasant. But I understood that for large values of the volume will be subject to extreme sound attack. But the sound radio receiver confuses the mind. I want to listen to this effect on the example of the theremin.
Posted: 8/26/2016 3:03:39 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Hello Valery,

I confuse myself all the time. My sound demonstrates complete use of the 40 cm dynamic range with a staccato at the whisper parts.

The circuit-board up above, without distortion all of the range.

Ideal Volume Control-3   .wav  6 meg

Christopher

You must be logged in to post a reply. Please log in or register for a new account.