Sound-Lab A-3 loudspeaker Electrostatics Speakers Pro & Con

Sidebar 1: Electrostatics Speakers Pro & Con


1) Uniform drive. The entire surface of the diaphragm is driven by the signal, rather than just a small area (footnote 1).

2) Because the diaphragm needs no stiffness, it can be very thin for superb HF transient response, and very limp for freedom from resonances.

3) True full-range designs have no crossover(s). There are no driver transition problems; the sound can be absolutely seamless, top to bottom.

4) Large radiating area is associated with less attenuation of spl with distance, providing a broader listening area.

5) Push-pull operation can yield very low signal distortion.

6) Dipole radiation minimizes first-arrival reflections from side walls.


1) Relatively inefficient; they tend to need scads of amplifier power.

2) Sometimes peculiar impedance characteristic complicates amplifier choice. They often work best with good tube amplifiers.

3) Because of multi-kV polarizing supply and high signal voltages, they can be less reliable than dynamics. Modern designs are extremely durable, but chances of breakdown are nonetheless higher than with dynamic systems.

4) Inherent marked tendency toward treble beaming, but there are ways of minimizing it.

5) Deep bass requires a very large diaphragm. Speakers may be humongous.

6) Large midrange radiating area impairs precision of soundstaging, relative to dynamic minimonitors.—J. Gordon Holt

Footnote 1: Uniform drive needn't result in uniform motion, however.—John Atkinson