Floorstanding loudspeakers — Westlake BBSM-10

The BBSM-10 is a three-way passive monitor from the BBSM series of Westlake Audio, the American speaker builder founded in 1971, whose president Glenn Phoenix is also its designer. The BBSM family runs from the compact BBSM-4 and BBSM-6 through the BBSM-10 and BBSM-12 and on up to the BBSM-15 main monitor. In its studio form the cabinet is laid out horizontally and finished in black utility paint. For domestic use Westlake also builds the BBSM-10VNF, an upright floor-standing edition in North American satin walnut veneer that carries the same driver complement in a taller box.

Key specs that matter

Two 10 inch woofers take the bass, a 6.5 inch cone driver works from 600 Hz upward and a 1.25 inch soft dome tweeter handles the top, all in a ported enclosure. The upper crossover point sits at 4 kHz. Rated response is 45 Hz to 20 kHz within plus or minus 3 dB, and sensitivity reaches 92 dB at 1 m for 2.83 V. Impedance is 4 ohms nominal with a 2 ohm minimum, and IEC power capacity is 115 W short term and 360 W long term. The studio cabinet measures 40.6 x 76.2 x 54.6 cm (height, width, depth) and weighs 68 kg. The vertical VNF version measures 116.8 x 36.8 x 49.5 cm, weighs about 90 kg, and its response is listed as 40 Hz to 18 kHz. The walnut model carries a five-year Westlake guarantee.

Engineering and use context

The filter network is a precision high level passive design with 109 parts, built into the cabinet and wired so the speaker can run from one amplifier channel or be bi-amplified with separate channels for the upper and lower sections. Inputs on the studio model are a heavy duty barrier strip rather than binding posts. In the walnut VNF cabinet the enclosure has extensive internal bracing and proprietary damping materials to keep panel vibration low.

Pairing

The low minimum impedance is a hard load, so the amplifier must be a solid state design rated for such loads and able to deliver high current for long periods. Bi-amping with two stereo power amps, one per frequency section, divides the current demand between two chassis, and each amplifier then sees only part of the frequency range. Its sensitivity figure is 3 dB higher than that of the small BBSM-4, so reaching an equal level takes roughly half the amplifier output.

Alternatives

A bigger Westlake floorstander is the BBSM-15F, which moves up to twin 15 inch woofers and a 10 inch midrange with 98 dB sensitivity.