Mini Diamond Theremin Speaker

To my knowledge RCA never made a "diamond" speaker.

The "original" RCA theremin speaker was the RCA-106 (http://www.radiolaguy.com/images/pre-1930/Theremin_106-1.jpg).

The RCA-106 is an open-back cabinet (http://www.radiolaguy.com/images/pre-1930/Radiola106-i.jpg) with only a dust cloth covering the back (http://www.radiolaguy.com/images/pre-1930/Radiola106-r.jpg). The bottom is wide open.

There are many audiophiles that prefer an open-baffle loudspeaker design - at least for the mid to high frequency drivers. The baffle is sized to the lowest frequency the driver is to produce. As you know, they require a driver with higher self-dampening qualities.

As coalport would certainly point out, a bottom end that is not fully supported can contribute to a more "human" vocal quality.

While the diamond speaker can be used as the sole means of sound projection, its main function is as a monitor for the thereminist (and dramatic prop). If you want earth-shaking bass...use a PA speaker or subwoofer.

Hi Jeff S,

All this time I forgot to point out that that's exactly what I use the diamonds for. They're my monitors. In my studio, they work just fine to fill the small room if a visitor is here, but out in public, yes, I carry along another amp which I put out on front for the audience.

I use the diamond mainly for pitch fishing, private performance, and rehearsals.

While looking around Amazon for stuff to use for making backdrops, and props, ect, I ran across these plastic fake decorative tiles that measure about 2 feet wide, and should make interesting detail plates for mini diamond speakers. Just cut out the circular center piece, and glue, or staple it on the front and or back of your diamond speaker.

http://tinyurl.com/3p7lkbk

Awesome idea Thomas! It looks like the center medallion is just about the right size for an 8" (200mm) speaker (cut-out).

Hello Jeff S. I was thinking the same thing. :)

Also realized that instead of gluing, or stapling, one could use velcro, or magnets to allow interchangable detail plates.

The detail panels just arrived today. They look fantastic! One type, the green and gold with red center medallion will require a 1 inch deep frame on the edge of the soundboard to accept the outer edge of the panel, while the other (copper panel) will go nicely on a totally flat soundboard. To finish the edges, I'm going to use antiqued brass, bronze or copper U-channel to seal the edges nicely. :)

By the way, if anyone's wondering, the panesls are exactly 24" square, and are plastic injection molded like a kids toy mask.

OH, Jeff-S, the center medallions on these penels can be cut to allow for several different sized speakers from about 6 and a half, up to about 10 inch speakers because of the various sized rings on the medallions. Pretty cool. :)

Just for fun, i'm posting a (very blurry, but you get the idea) photo of my new diamond speaker (http://www.dronestreet.com/diamond.jpg).

It's a wooden open-back cabinet, 16" square, with a 12" full-range driver. I made it square specifically so it could be "upgraded" to a diamond configuration by adding a bracket to one corner. I had the bracket made by a local fabrication shop in about an hour. It's just a simple "V" with a tube welded on the bottom, which fits on to a standard 1 3/8" speaker pole. The bracket attaches to the cabinet with 4 carriage bolts, and is easily removable so the speaker can sit on the floor if i'd rather.

It's pretty straightforward if you've got a square box handy.

-eric

The speaker cabinet looks great, but the big question is - what sort of speaker is inside it? Is it a high quality Jensen like the sort of thing Clara Rockmore used? Is it perhaps something you picked up on special in the automotive department of Canadian Tire over on Douglas St.? Then there is the matter of the kind of amp that's driving it.

The speaker i've got in there is not a PA or "instrument" speaker, but a full-range Philips hi-fi driver, (i believe AD12100/M8). It's powered by the amp section of my Keppinger-type tube theremin. I don't have a vast experience with different theremins and speakers, but it sounds fantastic to me.

Thomas, What kind of amplifier are you using? I have the same speaker only it is a 10". The amp I am using is an older PA amp but I am not totally pleased with the sound.