What's more important for sound?

Posted: 5/21/2020 3:09:43 AM
innominata

Joined: 2/9/2020

Bass shape: 60Hz, 150Hz, 330Hz

Posted: 5/21/2020 9:43:44 AM
JPascal

From: Berlin Germany

Joined: 4/27/2016

I guess - concern all what you has shown - that your pitch and volume parts are well. The more quadratic form in the lower register is probably due to RC filtering effects, whos time constant influences higher audio frequencies more than the lower ones. Try to enhance the coupling capacitors in the a.f. part of volume control and you will see an effect. 

But the loudspeaker signal is really complete wrong. May be there is a problem of shielding (pitch antenna has a couple of 100 volts r.f., straying in the circuit) into the audio amplifier / buffer unit. Also a wrong grounding or incorrect mass conections could be taken into account. Hope this recommendations are not too annoying, but without more knowledge of the concrete situation it is not easy to give more help. 

Posted: 5/21/2020 1:24:26 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

innominata, you have an audio amplifier of some sort driving the speaker, correct?

Posted: 5/21/2020 11:04:42 PM
innominata

Joined: 2/9/2020

innominata, you have an audio amplifier of some sort driving the speaker, correct?

I want to say no. The signal train is Mixer -> VCA -> PushPull -> Speaker.

Posted: 5/22/2020 1:50:24 AM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

Have you tried hooking the VCA output to an external amplifier & speaker (like a stereo, PA, guitar amp, etc.) ?

Also, driving anything significant off of the Theremin power supply can be problematic from a voltage regulation standpoint.  The oscillators can be quite sensitive to voltage variation.

Posted: 5/22/2020 8:02:53 AM
Valery

From: Russia, Saint-Petersburg

Joined: 6/6/2016

When the car is not going - first look at the engine and transmission, and last of all at the wheels. You can connect the speaker to another source for verification: radio, amplifier, or CD player... It's probably working. You compared the sound to site Christopher's sound. Are you working on this design?

Posted: 5/23/2020 11:09:44 AM
innominata

Joined: 2/9/2020

When the car is not going - first look at the engine and transmission, and last of all at the wheels. You can connect the speaker to another source for verification: radio, amplifier, or CD player... It's probably working. You compared the sound to site Christopher's sound. Are you working on this design?

No I'm working on my own design.

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