YL Sound 331A
Price unknown (1 unit, around late 1960 s?)
Commentary
A 30 cm cone type woofer developed as a woofer that matches horn type speakers.
By using an epoxy glass plate damper, high restoring force is realized, and hysteresis phenomenon is suppressed.
This epoxy glass is the same as the one used for pole vaulting and fishing rod.
The voice coil uses edgewise winding of copper ribbon wire.
It is equipped with a large magnetic circuit that uses Alnico casting for the magnet.
By adopting a cast frame, unnecessary vibration is reduced.
When used in a sealed type, an internal volume of 200 liters or more is optimum. If it is smaller than this, the apparent fo rises.
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Model Rating
| Type | 30 cm Cone Woofer |
| Voice coil impedance | 8 Ω |
| Lowest resonance frequency | 30Hz |
| Crossover frequency | 800 Hz or less |
| Rated input | 30W |
| Max Input | 60W |
| Output sound pressure level | 104dB |
| Equivalent mass | 32g |
| Qo | 0.1 |
| Total flux | 240,000maxwell |
| Magnetic flux density | 13,000gauss |
| External dimensions | Diameter 331x Depth 165 mm |
| Baffle opening diameter | 260 mm or 302 mm |
| Weight | 6kg |