Audio Database

363 WestBorough
Commentary

This speaker system was developed in pursuit of beautiful mid range and wide range.

The 363 WestoBorough has a structure with a 121 in the upper part, and the 121 part is in charge of the middle area, which realizes excellent middle area reproduction. In addition, the wide range is achieved by using a woofer made by Kusu Timas, a technology patented by Bose in the United States, for the low band, and a newly developed soft dome type tweeter for the high band.

The mid-range is equipped with D-222 which is a 11.5 cm cone type full range unit developed for 121.
While maintaining the previous size of 11.5 cm, the specifications of this unit have been renewed to provide the best performance. First of all, the cone paper achieve both high rigidity and moderate internal loss, the cone paper is carefully selected from a new material mixed with mica in pulp. In addition, a special cap made of glass fiber and a unique cone shape that takes high-frequency characteristics into consideration realizes a smooth high-frequency response.
In addition, Bose's unique helical voice coil with aluminum edgewise winding is used for the voice coil. With precise computer control, aluminum ribbon wire with square cross section is wound on the bobbin with no gap, and the gap between wires is effectively 0. This improves the utilization of magnetic field energy and achieves excellent transient response.
The frame uses Bose's unique injection-molded polymer material. This material does not magnetize the frame with the magnetism of the magnet, and shuts out the disturbance of the magnetic circuit.

A 2.5 cm soft dome type tweeter is installed in the high range.
This unit uses a very thin Tetoron for the diaphragm to suppress peaks and dips and make possible less colored sound. In addition, by shortening the stroke of the horn part around the dome, the wide directivity of the dome type is exhibited.
In addition, the magnetic circuit is filled with magnetic fluid to improve damping characteristics and reduce distortion components.

A 16 cm cone type woofer unit is used for the low range, and it is a acoustimass system mounted inside the base enclosure.
In this system, since the woofer unit is hidden inside the cabinet, acoustic energy is radiated outside in resonance with the air mass inside the port. Therefore, even if mid-range energy or strain occurs inside the cabinet, resonance does not occur because the frequency energy is different from the resonance frequency of the air inside the port. This acoustic filter effect cuts out high frequency strain.
In addition, the port outlet has been designed taking full advantage of hydrodynamics to prevent air jet energy from becoming turbulent, which not only eliminates port noise but also improves the reproduction efficiency of low-frequency energy.

In the Acoustic Kusu system, acoustic energy is radiated through ports located at the front and rear of the unit. Each port is tuned to a different frequency. Near the tuning frequency of port A, there is almost no output from port B on the front side of the unit. However, from port A, large acoustic energy can be obtained without moving the cone paper very much. Conversely, near the tuning frequency of port B, there is almost no output from the rear side and large acoustic energy can be obtained from the front side.
This structure allows both outputs to be combined in the region between the two tuning frequencies, resulting in a flat and high-efficiency bass over a very wide bandwidth.
The playback bandwidth at this port is a wide range of more than two octaves.

The enclosure uses MDF made from 100% conifer in pursuit of musical beauty.
In addition, the side panel is finished in a bird's eye maple style, and the surface is treated with a special UV coating that is hard to get scratches to increase durability.

The speaker terminal is a gold-plated screw-in type. This terminal is also compatible with a banana plug.

There was a special speaker stand sold separately.

Model Rating
Method 3-way, 3-speaker, Kusu timmass system, bookshelf type, magnetic protection design
Units Used For low band : 16 cm cone type
For Medium Range : 11.5 cm Cone Type
For high pass : 2.5 cm cone type
Impedance 6 Ω
Allowable input 80W(rms)
210W(peak)
Low flux leakage Canceling magnet system
Connection terminal Screw Type (Gold Plated) for Dual Banana
External dimensions Width 270x Height 581x Depth 264 mm
Weight 16.2kg
Sold Separately Dedicated Speaker Stand PS-3 (2 pcs 1 set, ¥ 22,000)