This Wikipedia article has a pretty good summary of advantages and disadvantages:
http://en.wikipedia.org/wiki/Electrostatic_loudspeaker
Among the many advantages discussed in the article, I would particularly emphasize clean transient response, i.e., the ability to stop moving instantly when the music demands it. The article addresses this with the sentence "Musical transparency can be better than in electrodynamic speakers because the radiating surface has much less mass than most other drivers and is therefore far less capable of storing energy to be released later."
I would add to its list of disadvantages the criticality of choosing the right amplifier. As was mentioned above, an electrostatic is, from the amplifier's perspective, essentially a giant capacitor. Therefore its impedance at high frequencies will dip down to very low values, perhaps 1 ohm or so at 20kHz (and a highly capacitive 1 ohm, not a resistive 1 ohm which would be easier to handle). The amplifier has to be able to drive that comfortably, but at the same time it has to avoid tipping up the frequency response at high frequencies, which would occur if the amplifier's output impedance is substantially less than the speaker's design is predicated on.
In other words, the lower the amplifier's output impedance (which equals damping factor divided into 8 ohms, and which is negligibly small for most solid state amplifiers), the greater the increase in current that will result from the speaker's diminishing impedance at high frequencies. If the output impedance of the amp is not a reasonable match to what the speaker designer intended, excessive brightness in the upper treble can result from that increase in current. In many cases, a tube amp will be the best choice.
Regards,
-- Al
http://en.wikipedia.org/wiki/Electrostatic_loudspeaker
Among the many advantages discussed in the article, I would particularly emphasize clean transient response, i.e., the ability to stop moving instantly when the music demands it. The article addresses this with the sentence "Musical transparency can be better than in electrodynamic speakers because the radiating surface has much less mass than most other drivers and is therefore far less capable of storing energy to be released later."
I would add to its list of disadvantages the criticality of choosing the right amplifier. As was mentioned above, an electrostatic is, from the amplifier's perspective, essentially a giant capacitor. Therefore its impedance at high frequencies will dip down to very low values, perhaps 1 ohm or so at 20kHz (and a highly capacitive 1 ohm, not a resistive 1 ohm which would be easier to handle). The amplifier has to be able to drive that comfortably, but at the same time it has to avoid tipping up the frequency response at high frequencies, which would occur if the amplifier's output impedance is substantially less than the speaker's design is predicated on.
In other words, the lower the amplifier's output impedance (which equals damping factor divided into 8 ohms, and which is negligibly small for most solid state amplifiers), the greater the increase in current that will result from the speaker's diminishing impedance at high frequencies. If the output impedance of the amp is not a reasonable match to what the speaker designer intended, excessive brightness in the upper treble can result from that increase in current. In many cases, a tube amp will be the best choice.
Regards,
-- Al