CW250B
active subwoofer
The conclusion was "bass extension" to "add depth and richness to music reproduction.
The "add-on subwoofer," which Fostex has been advocating since 2009, allows music to be expressed more realistically and passionately by easily adding on ultra-low frequency components that are difficult to reproduce even with large speakers.
Features
Enclosed cabinet
The basic cabinet design for accurate reproduction of ultra-low frequencies is to have a rigid, sealed structure that disperses resonance. MDF (18mm) is used for the rest of the board to disperse resonance and reduce incidental sound.
Maximum 34.6mm long stroke high efficiency 25cm woofer
The woofer has a highly rigid diaphragm made of a mixture of BKP pulp and Kevlar, a powerful 1.1 Tesla magnetic circuit, and a special voice coil (MFB detection coil) that perfectly reproduces 32 Hz, the lowest note of a 5-string double bass, and is capable of reproducing almost even 16 Hz of a pipe organ. The speaker edge material is made of durable, lightweight SBR foam rubber with high internal loss to reduce natural sound, and a long stroke of up to 34.6 mm is realized.
Motional Feedback (MFB)
The biggest problem with superwoofers is the increased group delay time. When playing a jazz trio with a bass reflex type, the bass performance can be heard delayed. The delay of a sealed type is about half that of a bass-reflex type, but MFB is effective for further improvement. This unit is a sealed type and further improved by applying 24dB of MFB at 60Hz, so you can enjoy the pleasure of the bassist supporting the bass player at the correct tempo.
A 300W PWM amplifier and fast response limiter provide stable maximum output sound pressure (106dB/60Hz).
ICE power of 300W is obtained as BTL operation, and feedback control with a high-quality sound response limiter with an attack time of 2msec (actual measurement)/release time of 700msec (design value) enables stable reproduction of a maximum output sound pressure sufficient for personal use.
Various connection methods for musical enjoyment and excitement
Connect the pre-output of the amplifier to the LINE INPUT of the amplifier. 2.
Connect the speaker output of the amplifier to the SPEAKER INPUT of the amplifier and the SPEKER OUTPUT of the amplifier to the speaker system. 3.
Connect the add-ons and the speaker system to the amplifier as usual, and connect the L and R sides to the SPEAKER INPUT of this unit. Stereo playback using two units, one on the L side and one on the R side, will reproduce the realistic sound of a concert hall.
Optimal crossover for add-ons
The crossover frequency of the low-pass filter can be varied continuously from 40Hz to 140Hz for optimum matching with the combined speaker system. The cutoff characteristic at the crossover point is set at 12 dB/oct. for the most natural synthesis, and the unwanted bandwidth above 270 Hz is cut off at 36 dB/oct. for clear sound field reproduction.
Specifications
Main Specifications
| Amplifier section | |
|---|---|
| form (something takes) | Woofer with built-in amplifier |
| Maximum practical output | 300W (JEITA 4Ω) at 100V AC |
| input terminal | LINE IN (RCA pin L-mono/R) SUB WOOFER INPUT (RCA pin) SPEAKER (HIGH LEVEL) INPUT |
| output terminal | SPEAKER THROUGH OUT LINE OUT (THRU BUFFER OUT) |
| Feature | PHASE(0°/180°) VOLUME control Crossover adjustment (40~140Hz) music source selector (SYMPHONY/ROCK/MOVIE) |
| Speaker section | |
| form (something takes) | Sealed acoustic suspension |
| Speakers used | 25cm cone type (simple antimagnetic type) |
| Output Sound Pressure Level | 90dB/W(1m)(JIS BOX)(Speaker) |
| comprehensive | |
| Maximum output sound pressure | 106dB/60Hz (all spaces) (+6dB for floor-mounted) |
| Power consumption | 50W / 11W with no signal |
| External dimensions | 340(W)×360(H)×398(D)mm (including grille and terminals) |
| mass | 19kg |
| accessory | RCA pin cable (3m) x 1 |