SONY APM-55W
¥ 108,000 (1 unit, around 1983)
Commentary
This is a bookshelf type speaker system announced as a core APM speaker.
In the APM speaker, the flat diaphragm eliminates the cavity effect, which is the resonance phenomenon of air that occurs in the conventional megaphone-shaped cone, and prevents the frequency characteristics from being disturbed.
In addition, the honeycomb sandwich structure used for the body of aircraft and Shinkansen is used for the diaphragm. This diaphragm with a hexagonal honeycomb core sandwiched between two sheets of skin material has 500 to 1000 times the bending composition of the conventional cone type, and deformation is suppressed to 1/20 to 1/30 even in actual use. This suppresses the generation of split vibration.
In addition, by adopting a square shape with a simpler division vibration pattern than the round shape, the division vibration is effectively cancelled, and unnecessary peculiarities are eliminated.
424 cm in the lower range2Uses APM type woofer.
A flat diaphragm with an aluminum honeycomb sandwiched between aluminum skins is used for the diaphragm. Four points where the low mode of divided vibration is concentrated are selected as driving points, and driven by an armature directly connected to a voice coil.
This effectively cancels the split vibration within the playback band, expands the pistic motion, and realizes high-resolution and tight low-range playback.
48 cm in the middle area2APM type mid-range is adopted.
The diaphragm uses a reinforced resin sheet as a skin material that is lightweight, highly rigid and has moderate internal loss. The drive system uses a large-diameter edge-wise voice coil and magnetic circuit.
12 cm for the high range2APM type tweeter has been adopted.
It uses a diaphragm that sandwiches an aluminum honeycomb core with a titanium foil skin and an edge-wise voice coil.
The network section is designed with an emphasis on sound quality, with boards for each of the three units and internal wiring of the oxygen-free copper and capacitors selected according to sound.
There was a special speaker stand sold separately.
Model Rating
| Method | 3-Way, 3-Speaker, Bass reflex system, Bookshelf Type |
| Unit | For low band : 424 cm2Plane type For Medium Range : 48 cm2Plane type For High Pass : 12 cm2Plane type |
| Playback frequency band | 31 Hz to 30000 Hz |
| Output sound pressure level | 91dB/W/m |
| Impedance | 6 Ω |
| Instantaneous maximum input | 200W |
| Rated maximum input | 100W |
| Crossover frequency | 450 Hz, 4.5 kHz |
| External dimensions | Width 385x Height 685x Depth 330 mm |
| Weight | 27.5kg |
| Attachment | Speaker cord |
| Sold Separately | Speaker Stand WS-500 (2 pcs 1 set, ¥ 8,500) |