Pitch Field Linearity II

IMHO: A theremin will work on batteries upstairs in a wooden house not using any sort of ground. This keeps the Pitch Field compressed as the Electro-Magnetic radiation RF must work harder to escape. A wrist strap may be all you need for some theremins.

A Hand Capacitance feedback loop is not the only effect that controls the Analog Pitch Field, with a tuned Pitch Antenna Xc shifting must be considered for what causes the better linearity.

Lack of earth ground also creates unwanted distortion in the natural Analog Theremin sound. RF is weird like in the “plasma gas globe” it crawls everywhere for lack of a better word looking for any conductive object in the room for escape. The electrical wiring in the walls is very inviting.

Important: This interaction with the electrical wiring within the Pitch Field reach is how 50/60 Hz flutter gets into the sound. The theremin approach senses changes of over 1:100,000 on the low end. Like your hand modulates the Pitch Field in the outer field so does the electrical wiring. It is best to keep the greatest distance between the theremin, outside conductive objects and the rooms walls.  50/60 Hz interference is my study for the week. When using the natural analog voice more than just simple filtering must be taken into consideration for a clean natural sound.

Ideal linearity comes about when the Antenna/Electrode resonates at the Pitch Oscillator frequency. With an un-tuned theremin Pitch Rod, lack of linearity will hinder your efforts to learn and be almost musically unplayable. In other words it will most likely be a waste of time to learn any real skill from an un-tuned Pitch Antenna. This makes the EtherWave Standard an excellent choice.

Maximum Pitch Field reach of six ideal octaves with ideal linearity is possible if the tuned RF energy on the Pitch Antenna/Electrode is maximum using the highest Pitch Oscillator RF frequency and earth ground, the Thereminist barefoot does make sense. This may seem like a capacitive loop but more is going on; it is the better conductive RF Pitch Field.

With ideal linearity the note positioning relative to one another remains the same no matter how wide a Pitch Field is stretched.

Keeping the above in mind six octaves at 4” or 10 cm spacing of Ideal Linearity can easily be played over a 24” or 61 cm Pitch Field, no octave switch or unnatural octave switching necessary.

All that I mention is my observations over time, others who feel threaten by change might challenge this post. Listen to the sound byte of any challenger or theremin designer to better know their understanding of how the theremin works.

This is my Analog Theremin Sound created by nature, I always say a theremin voice needing reverb is spiritually dead.

Christopher   

The Capacitive Hand Loop Model is based upon two capacitor plates with your hand being one of them. It does give basic understanding of the Pitch Field.

I am not trying to change anyone’s beliefs rather improve my own understanding. Where I have trouble with the loop theory is the resistance of the series loop using the hand as a capacitor plate connected to an imaginary wire back to the theremin seems too extreme in resistance for it to work unless using a wrist strap. Then you lose everything beautiful and natural about her voice.

This is why I believe Electro-Magnetic Energy is what the hand influences in a tuned antenna Pitch Field. When calculating a value for this it does seem like a variable capacitance loop, especially when using a wrist strap, yet maybe the energy leaving the Pitch Antenna is the “same formula expressed with different variables?”

Both methods agree the Pitch Antenna has the same electron movement that creates the Pitch field.  Is the Pitch Field an electro-static closed loop or an EMR/RF field pressing outward like the plasma globe into infinity, maybe a little of both? RF travels freely through the air, not electrons. RF passes even easier through the Thereminist, not electrons; this gets back to the experiment that a nearby un-grounded AM radio reveals the Pitch Field has RF energy.

How does the hand capacitive loop overcome the extreme resistance in the loop model? I use the 1.9” or 4.8 cm air gap distance for the shoes worn, standing on a wooden stage. Even with a good earth ground there are other obstacles that increase the resistance to electron movement in the capacitive loop path. A capacitor in series with an extremely large resistor, which is the Hand Capacitive Loop, is a very Low Pass Filter. What am I missing?

Understanding of how the theremin works is always revealed in her natural sound.  Another Sample mp3 from Nature. A theremin sound needing reverb to sound alive is spiritually dead.

Christopher

Air has an approximate resistance of 2 x 10^16 ohm-meter, everybody knows air is a good insulator from electron flow.

1 Meter = 39.3700787 Inches / 20 = 1.9" or 4.83 cm

1.9" or 4.83 cm equals a resistance of  .1 x 10^16 ohms

If my math is correct see below and the right side image is the capacitive loop resistance with only a 1.9" air gap.

Edit: dewster your continual nastiness and insults are actually amusing. 
.

"What am I missing?"  - oldtemecula

Everything?

[EDIT] You don't even know how capacitors work.  Here:

https://www.amazon.com/The-Art-Electronics-Paul-Horowitz/dp/0521809266

Get back to us if you have any questions - after you read it.  I'm seriously doing you a favor here, that's a fantastic book and an easy read.

I would never say my theremin sounds like a violin as a true theremin should sound like a true theremin. If you are faking your sound I guess it makes sense. Earlier this week someone posted this digital sound sample as their best violin sound to date, again what am I missing. Then he endlessly trashes daily everything I share, I guess to impress his hooligan friends. On the last day of Theremin World, at the end of the year, we should all get together. I will buy the first round of drinks, those that know me know I might just buy all of the drinks. Of course after I get vaccinated.

dewster you keep trying to prove something?

"... everything I share..."  - oldtemecula

All you "share" is fake science, and personal attacks on those who point it out. 

This thread was supposed to be about the physics behind pitch field linearity, but all we're getting is pictures of plasma globes, overly simplistic web C calculations off by 100, and rants about someone's violin patch.  Where's the beef?

You know, Touchless lives really near you.  His cornbread might not be done in the middle either, but if you two put your heads together you might just figure out how capacitors work (hint: it has nothing to do with DC resistance of the air).  Baby steps.

And, lest anyone think this is all just bickering, differences of opinion, or the airing of petty grievances that won't die:

I was hoping at least for the rationale behind how something that non-linear has "perfect" "ideal" linearity.

This thread might as well be about UFOs, free energy perpetual motion machines, or Bigfoot.

"dewster you keep trying to prove something?"  - oldtemecula

That not all Theremin designers are snake oil salesmen.

I enjoy when someone sends me an email expressing their understanding of Linearity. dewster please do not shit on him.
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Hi Christopher,

I've designed and built a few theremins over the years and just ran across your webpage. It's very well done and I enjoyed browsing through it. I have a theory about the antenna linearity that you have achieved, and since you asked for feedback, here goes. I believe you have perfected what has already been engineered into the RCA and Moog theremins. That is, a compound, stagger-tuned oscillator circuit that behaves the way we want. When more than one LC circuit are connected together with their frequencies carefully adjusted (staggered), the slopes of the resulting frequency response can be tailored. When the frequency of just one of those circuits is changed, the frequency of the compound circuit changes at a different rate than a single resonant circuit (as in most theremin designs) would. Check the Radio Amateurs Handbook or The Active Filter Cookbook by Don Lancaster for more on stagger-tuned circuits. I have actually modeled some of these things in Mathcad.

The LC in the pitch oscillator and the LC in its antenna form the compound resonant circuit. The player changes the frequency of the antenna resonator much more than the oscillator resonator resulting in a net frequency change that is less hyperbolic than a single tuned circuit would yield, and evidently more exponential (musical) after heterodyning. When you adjust everything right, you can find a spot on the curve that gives the desired result. The RCA theremin had an extra little coil in the pitch antenna circuit and the Moog Etherwave also has an antenna coil in addition to the oscillator coil to form a compound resonator. The Moog has decent linearity when properly adjusted, but not perfect. I believe the Etherwave Pro is real good, but I have never tried it.

I'm going to be designing a new theremin soon with many new concepts and features that I think is going to blow everyone's mind. I'll let you know when it's done and perhaps get your feedback.

Regards,

--Mark Barton
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Edit: dewster I am sad for you, you have a need to prove something. Your graph is something you created. You do not need to fear me, only your friend.

Edit2: The data did not originate from me either, this invites too much human error. Also the roll off seen is at the 8th octave, no one plays music above there only engineers trying to prove something.

Edit3: I hope you succeed with your synthesizer approach but because of your misunderstanding of how the theremin works, I expect a seasoned Thereminist to say your design has the wrong sound, feel & response. Fine for experimental music or toys.

"Your graph is something you created."  - oldtemecula

The data in that graph was clearly gathered by Valery in his Phoenix video, and I merely entered the data into a spreadsheet.  So, yes, I "created" the graph, but the data didn't originate with me.  If you are disputing the data itself then you'll have to take that up with Valery.  If you are disputing the way the data was graphed then graph it your damn self.  And all of this happened like 6 months ago and you didn't raise any objections then, the time for putting your "fake news" spin on this has long past.