Brand: SONY
Model: APM-77W
Year: 1981
The highlight of the Sony APM-77W is the use of flat drivers, the so called APM (Accurate Pistonic Motion) driver which is a Sony development. The diaphragm of the woofer uses a honeycomb sandwich structure in which an aluminum core is sandwiched by aluminum skins, and a damper is incorporated in the sandwich structure to suppress plate vibration. This diaphragm is driven at four points by four magnetic circuits and a voice coil. This solution is a 100 times more rigid structure than a regular paper cone and it offers a clear, precise and even dispersion of sound. The midrange and tweeter use similar construction while the crossover is composed of 3-individual network boards.
Technical Data:
3-Way Bass Reflex
Max. Input: 200 W
Rated input: 100 W
Frequency Range: 28Hz-30.000Hz
Impedance: 6ohm
Woofer: 530 cm2 APM
Midrange: 27 cm2 APM
Tweeter: 7 cm2 APM
Dimensions: 405x745x325mm (WxHxD)
Weight: 32kg
Available also in grey color.
Optional Speaker Stand WS-500
Original sale price: 4000 DM/pair in Germany