YAMAHA NS-570
¥ 60,000 (1 unit, around 1973)
Commentary
Based on basic research on NS speakers, this speaker system was developed with the aim of producing sound with rich musical quality and clear resolution.
The low-frequency band uses the NS type woofer JA 3504 b, which has its own patented structure.
Uses 66 φ large diameter aluminum ribbon wire edgewise wound voice coil.
A horn type tweeter JA-0506B is mounted in the high range.
Special hard duralumin foil of 30 μ thickness is used for the diaphragm, and the strength is increased by providing tangential corrugation on the edge.
For the magnetic circuit, 23 φ voice coil with aluminum ribbon wire edgewise winding, 40 φ magnet with air gap magnetic flux density 17,000 gauss and total magnetic flux 24,600 maxwell is adopted, and high efficiency of 110 db is realized.
The network part is designed by repeating trial listening and static characteristic measurement.
An air-core coil is used to avoid distortion due to the network, and a 0.8 φ formal wire is used to reduce DC resistance, prevent power loss and minimize characteristic changes.
An MP capacitor is used for the capacitor.
The enclosure is hermetically sealed and is a tall boy type which is rare at that time so as not to take up much floor space.
In addition, it uses a design with Brazilian Rose Wood on the top plate and snow white polyester paint on the side plate.
Model Rating
| Method | 2-Way, 2-Speaker, Sealed System, Tall Boy Type |
| Units Used | For Low Band : NS Type (JA-3504B) For High Range : Horn Type (JA-0506B) |
| Playback frequency band | 60 Hz to 20000 Hz |
| Lowest resonance frequency (fo) | 60Hz |
| Crossover frequency | 5 kHz, 12dB/oct., 18dB/oct. |
| Impedance | 8 Ω |
| Output sound pressure level | 92dB/W/m (New JIS) |
| Maximum allowable input | 45W |
| External dimensions | Width 429x Height 1108x Depth 343 mm |
| Weight | 40kg |