YAMAHA NS-630

Commentary

The NS 600 series 3-way speaker system pursues high performance that is not inferior to large systems even though it is small.

The NS 650 and NS 630 use different units for the woofer only.

JA 2055, a 20 cm cone type woofer, is used for the low range.
In this unit, the Qo of the vibration system is kept as small as possible by keeping the fo of the unit itself low (fo = 30 Hz, Qo = 0.30) against the rise of fo caused by the small enclosure with small internal volume. This realizes excellent characteristics of fo = 45 Hz even when the unit is mounted in the enclosure.
In addition, the voice coil has a large diameter of 52 φ and a long size of 20 mm coil winding width to realize a unit with excellent linear motion even at large amplitude. In addition, thermosetting polyester-imide resin is used for the insulating film and epoxy resin is used for the coil adhesive to enhance heat resistance.
The magnetic circuit uses a 120 φ ferrite magnet. The center cap is made of felt to prevent unnecessary high-pitched sound and to provide ventilation between the gap and the center pole to improve low-frequency playback.

For the middle area, 12 cm cone type skoker JA 1201 is adopted.
This unit has been developed exclusively for the 3-way mid-range. It employs a 42 φ heat-resistant voice coil and free edge. In addition, the fo is as low as 85 Hz, allowing sufficient allowance for the frequency band below the crossover to achieve a low distortion factor.

JA 0508, which is a dome-shaped tweeter, is used for the high frequency band.
Duralumin foil with a thickness of 30 microns is used for the diaphragm. In addition, by connecting the diaphragm and the edgewise winding of aluminum ribbon wire directly, the bobbin is eliminated and weight reduction is achieved.
An expanded urethane brake element is used between the diaphragm and center pole to obtain excellent high-frequency characteristics.

The coil used in the network section contains a ferrite core to avoid distortion caused by the network, and a 1 φ formal wire is used to reduce the resistance value of the coil to less than 1/20 (0.34 Ω) of the speaker impedance, thereby reducing power loss and characteristic changes. In addition, in order to eliminate mutual inductance of the coil, the coil is installed at right angles to each other.

Continuously variable level control for middle and high frequencies is mounted on the front.

By installing the middle and high frequency unit of the front baffle in the symmetrical position of the baffle surface, the characteristic fluctuation due to the diffraction effect is prevented and the flat characteristic is obtained.
The enclosure is 18 mm thick and fully enclosed.

Model Rating

Method	3-Way, 3-Speaker, Airtight Type, Bookshelf Type
Units Used	For Low Band : 20 cm Cone Type (JA-2055) For Middle Range : 12 cm Cone Type (JA-1201) For High Range : Dome Type (JA-0508)
Playback frequency band	45 Hz to 20 kHz
Crossover frequency	600 Hz, 5 kHz (12dB/oct.)
Lowest resonance frequency (fo)	45Hz
Impedance	8 Ω
Output sound pressure level (new JIS)	86dB/W/m
Maximum allowable input	40W
External dimensions	Width 280x Height 500x Depth 256.5 mm
Weight	11.5kg