YAMAHA NS-500

Commentary

A 2-way speaker system using beryllium diaphragm.

The low range is equipped with JA 2508 which is a 25 cm cone type woofer.
Cone paper is used for the diaphragm, which integrates the know-how of material research for many years, and the shape is a conical type which maintains the piston motion region up to the upper limit of the used band.
Urethane foam roll edge is used for the edge. In addition, the material and impregnation agent of the damper are newly selected to match the cone paper, and the center holding capacity and linearity are improved to suppress the sound collapse at large input.
The voice coil uses a short voice coil with copper ribbon wires wound edgewise. The bobbin of this voice coil uses DuPont's Nomex, which is heat-resistant at 220 ℃, to improve the input resistance. In addition, air holes are provided in the voice coil bobbin to equalize the air pressure inside and outside the bobbin. This reduces high-order harmonic distortion due to irregular motion such as the deflection of the voice coil.
The magnetic circuit uses an Alnico magnet of 55 φ x35H. In addition, the center pole is equipped with a copper cap to suppress the generation of the third strain caused by magnetic strain and the disturbance of impedance characteristics.
Aluminum die-cast frame is used for the frame.

JA 0516, a 3-cm dome tweeter, is installed in the high range.
The diaphragm uses a beryllium diaphragm with a mass of 30 mg or less. This diaphragm is made using the electron beam vacuum deposition method. It is made by applying an electron beam to a beryllium ingot to transform beryllium into atoms or plasma once, and then driving it onto a substrate (mother mold) to vacuum deposit it. This vacuum deposition method can also make deep domes that are impossible with press molding. In addition, since it is manufactured in a high vacuum, a high purity of 99.99% beryllium is achieved. The diaphragm is coated with a special 5 micron thick coating to protect the chemically active beryllium from harmful components in the atmosphere.
The diaphragm is directly connected to a heat-resistant aluminum ribbon and an edgewise wound voice coil. The edge is made of a special fiber tangential edge coated with two layers of viscoelastic resin and thermosetting resin.
The magnetic circuit uses a large ferrite magnet of 90 φ -45 φ -22t with a magnetic flux density of 17,500 gauss. In addition, the center pole is hollowed out and an air chamber is provided to keep the fo of the unit low and reduce strain. In addition, the center pole is tapered to avoid resonance in the space behind the voice coil.

The LC of the network is determined by repeating characteristic check and trial listening.
The coil uses an air-core coil made of formal wire with low DC resistance and large cross-sectional area to reduce distortion, and the capacitor uses MM type with good sound.

Equipped with continuously variable level control.

The enclosure uses a bass reflex system.
The board is an integrated structure made of high density conifer particleboards, reinforced in various parts to increase its strength, and sound-absorbing processed with newly selected glass wool.
The exterior has a black matte finish.

Model Rating

Method	2-Way, 2-Speaker, Bass Reflex System, Bookshelf Type
Units Used	For Low Band : 25 cm Cone Type (JA-2508) For High Range : 3 cm Dome Type (JA-0516)
Playback frequency band	40 Hz to 20 kHz
Maximum allowable input	60W
Output sound pressure level	91dB/W/m
Impedance	8 Ω
Crossover frequency	1.8 kHz, 12dB/oct.
Level control	Continuously variable type
External dimensions	Width 335x Height 610x Depth 338 mm
Weight	19.3kg