Etherwave antennas

The Moog Forum Theremin Forum
1

I am pretty much impressed so far by my Etherwave theremin. Good sound (of course) but also good range and reliability (and repeatability) about the antennas and their tuning.

I have noticed from pictures of Theremins over the years, the pretty much standard and traditional antenna style and arrangement, varying little overall over units, brands and years.

Not only am I aware of the critical sensitivity of things around the antenna, and tuning related issues, I am also making good of it. Which can only lead to one thing:

It seems to me antenna style and arrangements is well suited to the Theremin as a performing instrument, but what about some controller creative usage? Can the antennas be extended, located elsewhere, replaced altogether, doubled? And without creating impossible tuning issues because of changed capacitance or something?

I know a Theremin can be designed for alternate style antennas, but basically, has someone experienced antenna changes or extensions with their own Etherwave with good results (or lack of) and minimal trouble ? I bet there are some of you who have been experimenting with this. Let’s hear about it…

2

I know from experience that if I hang a patchcord over my volume antenna, it silences it completely. I can’t say how much capacitance it’s adding to the antenna, but it sounds like it really doesn’t take much to change the volume circuit’s response characteristics. I’m not sure how the pitch circuit would respond if I hung one off of its antenna…

BTW, this is my 300th post. (I thank you…) :wink:

3

That’s another question I have been meaning to ask : am i the only one using the volume antenna (unit off) to align patch cords to be used in a synth session? :wink: But I am more creative than using the antenna simply for holding patch cords, I find it works also absolutely well for headphones too :wink: Come to think of it : add a little net and there you go : your own beverage-in-a-can holder :wink:

Remote, extended, doubled antennas. Questions remain.

4

Well, I usually only hang the one short patchcord on the volume antenna to silence the Theremin when I need to walk away for a moment. I do that because it’s easier to maintain the original audio level that way. I would never abuse my volume antenna by using it to sort patchcords or hold my tasty beverage!

However, I do use it as a clothesline.

The pitch antenna also makes a great flagpole! It saves electricity and makes you look doubly patriotic! :wink:

(Where is that tongue-in-cheek emoticon???)

Bob :laughing:

5

It probably helps to think of the antenna as a capacitor plate, because that is what it is. Putting any metal or conductor in contact or very close to it increases the size of the plate, changing it’s properties. You can adjust for a tiny change with the pitch knob, and a larger change by making the appropriate internal adjustment, but even that has its limits.

An easy and effective way of enlarging the pitch field beyond its usual limits is by putting a CD on the top of the etherwave, next to the pitch antenna.

If you have an etherwave pro you can soften a CD over a candle then fold it and drape it over the arm like Dali’s soft clock.

(My rod currently has a festive star atop it - it is metallised plastic, and even that has made a difference to the field - but little enough that a quarter turn of the knob put it right.)

6

Thank you for your input Gordon.

Just put a CD on the unit, just like that? That seems easy enough to experiment with :wink:

I am doing good on large pitch field tuning (what i call the range), but it’s not that I am after. It’s getting clearer in my mind now what I want to do. The Etherwave is monopolizing too much resources for now (the Voyager and CP-251). So I have decided to dedicate the Etherwave it’s own MF-101. I am just back from the dealer with it and a couple of cheap expression pedals. I want to build a guitar/bass/mandolin control center based on the Etherwave, MF-101 and Midi-Murf (maybe a CP-251 too). A small custom designed console will contain the foogers and Etherwave’s main body, with antennas detached and located at places more suitable for guitar playing performance. That’s the plan anyway. I am ready to make some light engineering changes to the units provided I am guided in the right direction :slight_smile: Right now, I am contemplating these foogers and Etherwave trying to physically envision them in an easy to work with arrangement. A bit mind boggling given their odd shapes, sizes, knob and jack locations. Ohhh well… I might as well start sawing wood planks… one single piece at a time, from the ground up… ideas will come :wink:

7

Yup. I saw Jim Franklin do that at a German theremin fest so that he could step back and play his shakuhachi at the same time.

A small custom designed console will contain the foogers and Etherwave’s main body, with antennas detached and located at places more suitable for guitar playing performance. That’s the plan anyway. I am ready to make some light engineering changes to the units provided I am guided in the right direction :slight_smile:

Don’t do anything irreversible - theremins are specifically designed to be sensitive to the slightest change in their environment, which makes them hard to modify successfully.

Sorry, I need to rant now.

At the risk of belabouring the point - the metal sticky out bits on a theremin are not antennas, they are capacitor plates (aka electrodes.) I understand why everyone calls them antennas - especially the pitch rod - it looks like a darned antenna, and it’s connected to a circuit operating at radio frequencies, and if it looks like a duck and quacks like a duck, it’s a duck, right? Wrong. Do you know who didn’t call them antennas? Leon Theremin. In his patents he only mentions antennas once, in a sentence that says they are not antennas! Elsewhere he correctly calls them electrodes.

OK, rant finished.

So they’re capacitor electrodes. What does that mean? Question - how long is the pitch rod? About 18 inches? No - that’s just the bit outside the box. The stiff wire that connects it to the circuit board is part of it too. So it’s actually L shaped and about 24 inches long. If you open the box you’ll see a rectangle of metal foil on the base underneath the stiff wire. That affects the field. If you flex the stiff wire up or down a tiny bit closer too or further from the foil it will change the size of the pitch field. Just like putting a CD on top of the box in the same area. If you put another couple of yards of wire between the pitch rod and the circuit board, then you have just made the pitch rod eight feet long. No amount of internal tweaking will compensate for that. Fixing it to work with an eight foot pitch rod would require redesigning the circuit. Same for the volume loop.

So how about if you use coaxial cable like the one connecting your TV to its antenna? Nope - it’s still not an antenna, it’s a capacitor electrode, and the earthed wire mesh surrounding the wire would act like the other electrode - just like your hand does when you bring it very close to the pitch rod.

8

Be easy on me. I had never touched a Theremin, much less played one as of three weeks ago. I had the time to put together my own glossary about it. Not sure you care to hear the rest of it :wink:

Allright, MF-101 works well with Etherwave (wasn’t there supposed to be a LFO on that thing?). Gonna conduct remote capacitor rod experiments anytime soon now. Where’s my pipe wrench ? :sunglasses:

9

Knock yourself out. :slight_smile:

Delay pedals are excellent with theremins.

10

Delay pedals with reverb!

:smiling_imp:

11

The cd trick is effective it seems. I made only a quick test, but it did extend the range about threefold on a tuned machine. It’s location is quite critical. One quarter inch to the left it ceases to work, one to the right and the good tuning, extended range or not, is gone.

Extended range will be very helpful. Remote rod experiment turned disastrous. I used a hollow body (an antenna in fact) rod on a tripod in the middle of the room. It was reacting a bit, but the whole pitch of the machine climbed up high, with no possibility of tuning using the knob only. I wanted to try using a few electronics components connected in between, but the initial results were too far off what I expected. Maybe I’ll get back to it at some point but for now, I consider the Etherwave’s component too critically matched together as a unit.

Not doing too well on the Etherwave+guitar center either. I had planned to replace the Voyager’s filter processing with the MF-101, which I thought was essentially what I was doing with the Voyager. MF-101’s filter works well (nice to have resonance on a pedal), but there’s no LFO to work with anymore, and I now realize I was tapping into other resources of the Voyager in my guitar processing, such the 3rd Osc, both mod busses and more elaborate envelopes.

The set-up is going to need more work and components to become really interesting. I wanted to do away with the MP-201 on this rig, but I finally called it in, along with my new Step 64, which I used midi connected to the pedal sending CV sequences to the MF-101’s input (filter cut off works well, as expected). Interesting textures to say the least, so i’ll continue exploring with the MP-201, MF-101 envelopes with the sequencer, and try to fit at least one LFO channel from the pedal in there somewhere.

12

Hi Everyone,

I’ve been lurking on this list for a while, and Gordon has now dropped my name, so I decided it’S time to come out of the closet.

My main instrument is shakuhachi, but I also play theremin, generally EWPro with a bunch of MFs and delay pedals attached, but also an EW standard, hotrodded by me with volume cv and pitch preview. In working with both theremins, I’ve wanted to play shakuhachi and theremin simultaneously. My solution has been to modify (non-destructively) the theremins’ pitch characteristics, so that the field is much wider than for hand playing. This means that I can control the pitch by large-scale movements of the whole body, rather than the hand. So I can dance around the theremin while playing the shakuhachi, using vertical motions of the end of the flute over the volume loop to control volume, timbre (via cv to MF101) etc.

On an EW standard, simply placing a standard CD or CD-R next to the pitch antenna does the trick. How close it is to the antenna determines the breadth of field. I usually set up so that I have about 1 1/2 octaves in a 90 degree body sweep. On the EWPro, the Dali-droopy CD works in the same way. You slide it along the pitch arm to change the sensitivity.

BTW, the pitch antenna of an EW standard can be replaced without harm by a metal disc about the size of a standard CD, connected to the screw thread where the antenna would normally be, by an alligator clip. Sensitivity is modified by exact position of the disc on the cabinet, and distance vertically above the cabinet (spacers can be made from thin sheets of polystyrene foam). I used this trick once for an art installation performance, where the EW was to be completely covered by a cardboard carton, and no-one was to see what I was doing to make sounds. Pitch accuracy suffered, of course, but somehow I got away with it. This is what gave me the idea of the sliding CD.

Hope this helps…

Jim F.

BTW, on my website somewhere, there’s a picture of me in performance with shakuhachi and EW standard - a festival in Japan a few years ago. The site is in German, but non-German speakers can click through and find the pic:

www.bambusherz.de

13

PS, I forgot to say that I agree with Gordon about the nomenclature. The antennas are capacitor plates. Putting a CD on the cabinet etc changes the characteristics of the dialectric (the space between the implicit plates, in this case antenna and earth) if it’s not touching the “antenna”, or the size of the plate if it is. We’re talking very small capacitance values here, so changing the nature of the dialectric in a small way can significantly affect the response by affecting the capacitance of the implied capacitor. This is really what is happening in playing the theremin with the hand, as I understand it - the body itself is changing the characteristics of the dialectric, as much as directly altering the capacitance as an extension of the “earth” plate.

However, popular usage and convention call the things sticking out of the theremin “antennas”, so we’re probably lumbered with that designation for all time…

Cheers,

Jim F

14

Hi Jim, thank you for your input and welcome to the group.

While I am seeking everything I can on the Etherwave, I am pursuing my own ‘testing’ to improve my set-up and Etherwave’s range and performance as a controller.

I tried to find compatible fittings and tubing for more antenna experiments. No success yet but i’ll keep an eye open. I am not really expecting wonders on that front, and pretty much scrubbed of my plans for remote antennas (rods) for now (but i’ll be back).

So what’s left to do? Make the best of what is. The microphone stand fitting underneath the unit and the Etherwave’s low weight were the keys to my next plan.

I pulled my Voyager’s rack away from to wall to get some clearance. I made a coupler for the microphone fitting and hiked the unit on top of a high tripod with a tiltable base (designed to handle cameras 5 times the weight of the Etherwave). The unit is now a feet higher than the shelf holding my foogers, slightly to the right of the Voyager, the top of it’s case pointing directly to where I stand to play the Voyager. There is enough clearance for the Etherwave to function normally in it’s jacked up position. Luckily, I am tall and all the knobs are accessible when I extend the hand. All the wiring flows down naturally exactly where it’s going to be used, and there is much less wiring in the room where the Etherwave used to stand.

This arrangement turned out pretty good. I can now play the Voyager with the Etherwave waiting idle, and presto, when I raise hands, I can play Orchestra-Conductor-Hero of a symphony of CV’s (well 2 +gate loll) playing whatever parameter I plug into. Better than good, pretty much what I was looking for.

That pretty much took care of the Voyager. Setting the Etherwave for the guitar rig following the same idea also gave very good results. This time, the unit is about at shoulder height, with the top of the unit 90 degrees from vertical, knobs pointing down, easy reach. Everything is out of the way, the guitar neck can be brought more easily to either antenna. Very good control when I play the bass with my back toward the unit, playing both CV’s simultaneously. The tripod is steady and safe enough to grab and move around. Height is a matter of taste. Sometimes I like it with the unit higher and pointing downward a bit. The heavy duty tripod makes it easy to change height, and the unit can be brought back upside up in a flash with tiltable base. Here again, a tremendous improvement in performance. I still would like to maybe ‘re-orient’ the pitch rod, something like a ball fitting to couple with the rod instead of a fixed 90 degrees fitting. But as it is, it’s good.

That’s how a simply idea turned out working better than all my mods plans :wink:

All the while I found out that the Gate CV works extremely on the Etherwave (so perfect to trigger envelopes). Also, my little MFB Step 64 is sequencing filter cut-off frequency when processing Etherwave audio, to the nicest effect. The Step 64 can sequence 4 CV’s simultaneously, and I have tapped into pitch and envelopes with interesting results. However, dealing with more than one CV with the sequencer is something you have to invest some serious time in, kinda like programming a good pattern for the Midi-Murf.