Electrostatic and Ribbon speakers are well known by audiophiles for their low distortion and high precision.
Electrostatic and ribbon (also known as Planar Magnetic speakers) use the same principle to produce sound. A thin panel vibrates air between positive and negatively charged stationary panels. The result is a very accurate and detailed sound. Their ability to respond to dynamic changes in audio soundtracks exceeds the ability of conventional cone and box drivers.
The speakers look nothing like conventional dynamic speakers. These speakers are usually tall, wide and can be wafer thin and sometimes look like a large screen you can actually see through.
It is for this reason that a sub woofer is an absolute must when using Electrostatic or Ribbon speakers for home theater. Many electrostatic and ribbon speaker designs incorporate conventional drivers along with the speaker, giving the listener the best of both worlds. But this design is difficult to build. Matching between the electrostatic and driver speaker requires meticulous engineering, so they are sure to be expensive.