EQ settings for theremin

These days I am fiddling with EQ. A guitarist has lent me one of these: http://www.ehx.com/products/tube-eq - I'm aware it's probably not the best unit for a theremin, but as they say, "don't look a gift horse in the mouth", so I'm trying it (it's also the first time I get my hands on vacuum tubes. They are beautiful when they light up - do they really need to light up in order to work, or is it just that these units include some LED to light them up for the show? Sorry if this is an obvious question, I'm young and I'd never seen a vacuum tube working before).

At the beginning I wasn't getting anything good out of the unit, but after trying several settings I managed to make my theremin sound (subjectively) somewhat better than without it. My goal is to make my Etherwave Plus sound as warm and as close to an RCA as possible (I know it's impossible to get there with an EQ unit, let alone a sub-$200 one, but if I could get 10% of the way there, that would be nice). I think I have learned the following:

- It's better to change the settings very gently because the extremes don't give good results (at least for what I want, of course); and a slight change can provide a noticeable improvement (or the opposite).
- I prefer to set the "Q" option (the harshness of the bandpass curve) to a relatively low value, high values seem to give a too bright sound.
- A slight boost of the mid frequencies (with a relatively low center frequency) seems to work well.

These are my impressions as someone that has no idea of EQ, and just read some websites to see how it works and fiddled with the knobs. I would be grateful to get any opinions, suggestions, alternative settings, etc.

Vacuum tubes have a heating filament which is needed to heat up the cathode, so that it can emit electrons. The heating parameters of most tubes are 6.3V 300mA which makes a heating power around 2W. So the glowing and the heat are not for pleasure but basic requirements for the correct working of a tube as is also the relatively high (lethal) plate voltage (>=170V) which is needed to attract the stream of electrons.

You will never get a real RCA sound by equalizing an Etherwave. The miracle of the RCAs happens already at the mixer stage which is responsible for a timbre (harmonic content) which varies very much depending on the audio frequency (thanks to asymmetric soft-clipping and coupling effects). That means that your Etherwave should output even more harmonic content (which it does not) and you had to apply a different eq-setting for every tone...

AlKhwarizmi said:

“My goal is to make my EtherWave Plus sound as warm and as close to an RCA as possible (I know it's impossible to get there with an EQ unit, let alone a sub-$200 one, but if I could get 10% of the way there, that would be nice).

The nice thing about the vacuum tube is it gives you “many voices” (-‘. Thierry says the miracle happens in the mixer stage and I totally agree, this is where the magic takes its "shape". I use tubes (125v plate) only for the two pitch oscillators; Thierry prefers tubes in the mixer and later I believe.

I have a sub-$200 easily, complete tube/valve hybrid home build theremin in the works if you can etch your own circuit boards. What I use for tunable coils is amazing and cost $1 each x 4, you should peek. It is probably a year away before all this becomes available. The electronics are finished, hear it below. My trouble is I am forced to work alone. No Master Thereminist or anyone to evaluate the behavior & performance, no cabinet makers to make it pretty and no one nearby with electronic skills to validate my electronic design parameters, I know the basics and a little more and then some more.

One time one of you pointed out I had 60 Hz hum in my sound which I could not hear at all. I later figured it out, ground those dang heater elements. This is direct theremin (TL082) to my sound card. Can’t play, all I can do is share sound bytes; I know that’s entertaining for someone. (-;

What sounds interesting today always sounds horrible tomorrow!

My Enigma Hybrid Tube Sound: enigma 3  .mp3 150k

Happy Holidays to All!

Christopher

"So the glowing and the heat are not for pleasure..." - Thierry

Yes, but can we not take pleasure in them non-the-less?

RS Theremin - The "'sound" of your Enigma is not bad, however the volume response seems a bit abrupt. Granted, we cannot actually see what you're doing to create that sound. Personally, I would prefer one with a smoother volume response.

You can find no competent theremin players in the San Diego area?

Hello Jeff,

I hope we are not highjacking the thread.

Interesting, you have brought this subject up before, do you only see the tree and not the forest? I do not have playing skill.

By your interest I recorded another sample slightly different timbre, spread to 10" shading to emphasizes my ideal volume control design with absolute cut-off. This trait is kind of like my ideal linearity, so ordinary now it is not something I think about.

Another Enigma Hybrid Tube Sound: enigma 7  .mp3 150k

Jeff we have been around a long time [b]Post Something[/b] for me to hear.

Christopher

That's the beauty of senility. You can say the same thing over and over again, and it seems like the first time you've heard it. :-)

Did I say something wrong? I thought you were actually soliciting opinions about your prototype theremin. I don't recall making any comments about your playing. I will take your challenge into consideration, but I don't know what I can offer that you haven't heard before or much better.

My apologies to AlKhwarizmi. It was not my intent to highjack his posting. Actually, I thought we'd be hearing from coalport any minute to learn all about the fine art of equalization.

Jeff S said:

[i]"Did I say something wrong? I thought you were actually soliciting opinions about your prototype theremin. I don't recall making any comments about your playing. I will take your challenge into consideration, but I don't know what I can offer that you haven't heard before or much better."[/i]

Just having fun here and there is no Thereminist I have heard here locally that would have interest in me,or me them.

I don't think we are highjacking, the thread is about vacuum tube timbre.

Here is my first attempt at a song, first run through. With so many years of testing, I am bound to get an understanding of the finger movements somewhat.

My First Song  350k - - YouTube look out!

I don't know what my volume hand is doing, I am not aware of it, then I forget the rest of the song!#$%

OK...since the damage has already been done, I'll at least finish by conceding to Christopher's request. Look here (http://www.thereminworld.com/forum.asp?F=3&T=5237&cmd=p) for a link to a sound file (if you haven't already).

My apologies once again to AlKhwarizmi. At least it is tube theremin related, so it's not terribly off topic.

Hello Jeff,

Your sound byte is nice. Now I understand what you mean by my over emphasis in my "avant garde" sound control.

Actually I am looking for something which is inherent in the way I do research. If you have peeked at my present day osc board design, not important, it looks like surgical tubing running off of Sir SineWave Frankenstein. My trying to play a song actually made my sound boring.

I get these inspirational moments and I just know there is a method to extract an original sound from heterodyne behavior that just might be new and musical.

I try and document notes but it would be easier to keep track of stock market ticker symbols passing by.

This is what I believe AlKhwarizmi is talking about, trying various methods and looking for "the perfect wave" or timbre using every means available!

I need another beer!

Yes, my goal is to try to get as pleasant a sound as possible... although since I don't have the knowledge to fiddle with the innards of my theremin (let alone buy one), I have to try to get as much as I can out of a meager EQ unit :)