YAMAHA NS-550
¥ 45,000 (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 3505 b, which has its own patented structure.
52 φ large diameter aluminum ribbon wire edgewise wound voice coil is adopted.
A short horn type tweeter JA 0505 is mounted in the high range.
The diaphragm is made of 30 μ m thick Djelal Ming foil, and no bobbin is used to lighten the vibration system. The diaphragm and voice coil are directly connected, and aluminum ribbon wire is edgewise wound.
In addition, an expanded urethane brake element is used between the diaphragm and the center pole excellent high-frequency characteristics.
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 snow white polyester coating on the top plate and American walnut oil finish on the side plate.
Model Rating
| Method | 2-Way, 2-Speaker, Sealed System, Tall Boy Type |
| Units Used | For Low Band : NS Type (JA-3505B) For High Range : 5 cm Short Horn Type (JA-0505) |
| Playback frequency band | 60 Hz to 18000 Hz |
| Lowest resonance frequency (fo) | 65Hz |
| Crossover frequency | 5 kHz, 12dB/oct. |
| Impedance | 8 Ω |
| Output sound pressure level | 91dB/W/m (New JIS) |
| Maximum allowable input | 36W |
| External dimensions | Width 402x Height 1021x Depth 303 mm |
| Weight | 32.5kg |