Sony APM 750AV (c. 1986)
A mid-range, AV-compatible bookshelf speaker from Sony's APM series, featuring flat diaphragm drivers and a passive radiator for extended bass.
Overview
The Sony APM 750AV is a passive, bookshelf-type speaker system released around 1986 as part of Sony's APM (Audio Perfection Module) series. It was positioned as a mid-range model designed for high-fidelity audio and AV use. The speaker uses flat, square diaphragm drivers instead of conventional cones, a design intended to reduce distortion and improve transient response. It features a magnetically shielded enclosure and includes an ABR (Accurate Bass Radiation) passive radiator to enhance low-frequency output. The system is equipped with an automatic recovery type protection circuit to guard against overload.
Specifications
| Type | Bookshelf Type |
| Enclosure | Passive Radiator |
| Way system | 2 |
| Unit For low band | 170 cm² Plane type |
| Unit For high frequency | 9 cm² Plane type |
| Playback frequency band | 40 Hz to 20000 Hz (some sources cite 20 Hz to 20000 Hz) |
| Output sound pressure level | 89dB/W/m |
| Rated input level | 50W |
| Maximum instantaneous input level | 100W |
| Impedance | 6ohms |
| External dimensions | Width 280x Height 525x Depth 220 mm |
| Weight | 8.5kg |
Design
The APM 750AV uses flat, rigid diaphragm drivers for both low and high frequencies, differing from traditional cone designs to reduce distortion and improve transient response. It incorporates an ABR (Accurate Bass Radiation) passive radiator to extend bass response and is built with magnetically shielded drivers to prevent interference with nearby CRT displays. The system includes an automatic recovery type protection circuit to safeguard the drivers during high-volume operation.
Reception & Use
The APM series is noted for its bright, detailed sound signature, with owners praising the clarity and unique appearance of the speakers. However, their revealing nature means they can highlight imperfections in source material. Some users have reported degraded foam surrounds requiring replacement, a common maintenance issue with aging units.
Market
Used pairs of APM 750AV speakers have been listed for prices ranging from $50 to over $400, depending on condition. Foam surround degradation is a known issue, but repair is supported by the availability of a service manual.
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