Flat-panel speakers should soon sound far better, says Anthony Hooley of 1 Ltd in Cambridge, UK. Most speakers use a moving panel to create sound waves. But the rear of the panel creates the same sound but with the opposite phase. Unless it is trapped inside the speaker cabinet, it mixes with the sound from the front, and the waves cancel out, giving poor sound.
Hooley’s new speaker uses two parallel flat panels with a coil of piezoelectric material in between (WO 2004/28199). Current fed through the coil pushes and pulls both panels in step, but in opposite directions, so the sound is louder and there…
