MartinLogan SL3 loudspeaker Trying to Control a Lightning Storm part 2

Phillips: I suspect we're getting ahead of ourselves.

Sanders: True, our first transducer had none of those elements. I built that first speaker right out of a hardware shop: perforated aluminum for the stators, Plexiglas for the spacing elements, epoxy glue to hold everything together. I found some half-mil polyester film somewhere and sprayed insulation onto the stator. To get a conductive coating onto a diaphragm, I burnished graphite onto the film.

Phillips: You just rubbed it into the polyester?

Sanders: That's right. It gives a nice semiconductive surface—you don't want a totally conductive surface on the diaphragm because all you want to do is establish a bias charge, so the more resistive the surface is, the better off you are. That keeps the charge from migrating.

I had the basic elements together, but my strengths were in physics and mechanical design—I was not really a sophisticated electrical engineer. I met Ron Sutherland by chance and mentioned that I was designing this speaker, and that I needed someone to design the power supply. He said, "Oh, I'll do that." That was the beginning of Martin-Logan. The name comes from our middle names.

We finally completed the speaker and hooked it up to a little Hafler power amp. It worked! It looked like something right out of a barn—it was 2' by 3', with bare metal stators and wires hanging off it—but it worked right out of the chute. We'd chosen the right power supply, the right spacing element, and the right transformer. There wasn't much bottom end due to dipolar rolloff, but the midrange and the top end were transparent, immediate, and open. It was glorious. Tears were running down Ron's cheeks. We'd been working on this for a year and a half, and it had paid off.

Flushed with success, I uttered those famous words: "Let's turn it up!" A lightning bolt shot across the panel with a loud crack, followed by absolute silence and a curl of smoke rising from the stator. We had just experienced the power of an electrostatic loudspeaker—about 5000 volts had ripped a huge hole in the diaphragm, burnt away the insulation, and blown up the amplifier.

That's when the real research started. We went back to the drawing board and tried to figure out why it had happened, and how to prevent it in the future.

Phillips: Wouldn't a sane man have said, "Oh, this is why nobody is doing this," and walked away?

Sanders: Exactly. Anybody else would have said, "This is why we need dynamic speakers." What did I say? "I'm going to start a company to make more electrostatic speakers."

Phillips: Really? At the point of failure, you decided to make it your business?

Sanders: No, not really. But neither were we deterred. We knew that the only way to make a successful product was to address reliability, longevity, dynamic range, and full-bandwidth response. So we knew, even before we had a successful electrostatic transducer, that we would have to design a speaker that coupled a dynamic woofer with a workable electrostatic driver.

What had given hybrids a bad name up to that point was that they were designed by specialists in planar speakers—the dynamic driver was practically an afterthought. We knew, long before we had the planar element designed, that we would have to do a better job with the woofer than anyone else had, or we wouldn't have a product that people would want.

From the get-go, our first product had to be the Monolith. I knew the panel had to be 48" tall, so that you had even frequency response whether you were standing or sitting; and I knew, since it was a curvilinear line source . . .

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