In the 1980's, Quad released the ESL-63. It began what I call the modern Quad electrostatic loudspeakers. The modern line started with the ESL-63, then was followed by the 988, then the 2805, and then the 2812. When the 988 was released, Quad also released a larger speaker with 50% more panel area designated the 989. This larger speaker was followed by the 2905, and finally the 2912.

The modern Quad ESLs use a sectionalized panel approach like the original ESL, but unlike the Original, all the stator spacings are the same, and the panel area is divided into 8 annular regions. The center region plays full range, and moving outward the signal is delayed and the high frequencies are filtered out in subsequent rings. This technique makes the flat panel radiate a wave front that is similar in geometry to a point source located a short distance behind the speaker.

Quad ESL-63 electronics.

Quad ESL 988/989 electronics.

Quad ESL 2805/2905 electronics.

Quad ESL-63 split mid/treble panel

Quad ESL 2805 with grilles and dust covers removed

Quad ESL-989 getting panels rebuilt

Modern Quad Electrostatic Loudspeaker References

ER Audio in Australia is a great source for mylar, coatings, power supplies, input transformers and complete ESL kits. His prices are very good, and they ship promptly. Mylar is very well packed in a double mailer tube arangement. The products and service I've gotten from these guys is first class. I highly recommend them.