YAMAHA NS-470

Commentary

This is a bookshelf speaker system developed by integrating sound technologies developed by Yamaha.

For the low range, it is equipped with 25 cm cone type woofer JA-2503 which is made by mixing special synthetic fiber into the cone pulp to suppress the division vibration of the high-end.
In this unit, in order to achieve high input resistance, the voice coil is edgewise wound with heat-resistant wire equivalent to 4-layer winding, and adhesive with excellent heat resistance is also used. In addition, the center pole is equipped with a copper cap to suppress the increase in impedance and the generation of distortion in the mid-range.

A 4.5 cm soft dome type tweeter, JA 0511, is mounted in the high range.
As with the NS-690 and NS-670, the diaphragm of this unit is made of a material with double coating of thermosetting resin and viscoelastic rubber resin. It absorbs divided vibration and provides sufficient rigidity in the operating band. This coated material is molded together with tangential edges by hot plate press. In addition, a hole is made through the outer pole to release air at the edge and smooth movement of the edge to improve linearity.
A heat-resistant voice coil and FRP bobbin are used for the magnetic circuit.

By using aluminum die-cast for the frame of each unit, sound quality degradation due to resonance is prevented.

The network section is designed by repeating characteristic checks and trial listening to determine constants.
A level controller is also provided for the tweeter.

The enclosure is hermetically sealed with high-density particleboards and is reinforced and filled to eliminate noise and resonance.
Also, it is finished with Castor (stopper).

There are 3 kinds of net grills, プルネラブルー and Jankas Green besides Mulberry Red in the picture.

Model Rating

Method	2-Way, 2-Speaker, Airtight Type, Bookshelf Type
Units Used	For Low Band : 25 cm Cone Type (JA-2503) For High Range : 4.5 cm Dome Type (JA-0510)
Playback frequency band	50 Hz to 20 kHz
Lowest resonance frequency (fo)	50Hz
Crossover frequency	2 kHz, 12dB/oct.
Output sound pressure level	90dB/W/m (New JIS)
Maximum allowable input	60W
External dimensions	Width 300x Height 577x Depth 279 mm
Weight	14kg