Electrostatic Speakers

A friend of mine calls to tell me about his recent purchase of Martin Logan’s. At first, I can’t understand what the big deal is about a pair of boots. Oh wait, that’s Doc Martens. Phew, I really don’t see him as the skinhead type. I am given a clue as he continues on.

“You have to come and listen” he says.

Ah ha! Let’s see; a radio, stereo, headphones? Not quite. He is talking about a pair of speakers. The next thing I know he’s tossing about words like electrostatic and high-performance. All I can summon to mind with electrostatic are those plasma lightning lamps. Just when I realize my friends aren’t talking about their pets when they mention woofers and tweeters, here comes something else I have to learn about, or get left behind in the technology age.

We make our way to his home and he seats us in the center of the room so we can enjoy the full effect. My husband and I smile politely and nod our heads as he spouts technical terminology. The speakers themselves look odd. The top portion resembles something my husband might rig together with leftover chicken wire, but the sound coming from them is incredible, and we are enveloped in pure harmonic heaven. At the end of our concert we go home and I boot up the PC for some schooling.

I learn that electrostatic speakers use a light weight diaphragm, usually made from polyester film, sandwiched between two electrically conductive grids. This is the part that reminds me of mesh wire. The polyester film has been impregnated with a conductive material like graphite. The diaphragm operates with a constant charge (rather than voltage) on its surface. Both grids, one on either side of the diaphragm, are necessary because the force exerted on one grid would cause harmonic distortion. The diaphragms must be driven by an external source of high voltage. This explains what my friend was going on about when he pointed to the new amplifier to go with his speakers.

The advantages of electrostatic speakers are that they are extremely light weight and produce exceptional sound, because the generating force and pressure is not prone to resonance. The down side is the lack of bass response. This is why Martin Logan’s are considered hybrid. They incorporate a subwoofer to handle the lower frequencies.

Electrostatic speakers have been around since the 1920’s, so why is it news to me? It seems the earlier versions were fragile, and with advancement in traditional speaker design, and inexpensive materials, enjoying music in the home became more affordable. However, if you enjoy purity of sound without the crackle and pop that traditional speakers sometimes deliver, check a pair of these babies out for yourself. While a bit on the pricey side, the concert quality is pure enjoyment and well worth the investment.