B&W Invokes Big Bass From Small Space

Bows Very Compact High-Performance Active Subwoofer

18-May-00

Britain's B&W Loudspeakers, for over thirty-five years a world leader in loudspeaker technologies for music and home-theater systems, has introduced a powerful new amplified subwoofer that defies conventional concepts of what high-performance subwoofer means. The B&W ASW 2500 measures just 12 by 12 by 15 inches, weighing in at a svelte (for a high-performance subwoofer) 50lbs. Yet despite its diminutive size the latest B&W sub offers bass extension and bottom-octaves musical performance that equals its late, much larger ASW 2000 sibling in nearly every way, making it an ideal choice for all but unusually large rooms.""We are very much aware that B&W has numerous customers who demand the very best performance available, but who also require the most space-saving design possible,"" says Chris Browder, B&W's Executive Vice President. ""Many of these folks simply cannot consider a large, high-performance sub. That's who we created the ASW 2500 for: performance-conscious audiophiles and serious home theatre fans who demand big, fully extended, powerful bass but are unable to accommodate a conventionally sized high-end sub. The new model's remarkable size lets it ëdisappear' into the room in a way that larger, conventional woofers simply can't do.""The new ASW 2500 occupies far less than one-third the volume of B&W's previously impressive 12-inch ASW 2000, (and about one sixth that of the 15-inch ASW 4000!) yet its effective range is very nearly identical, with useful output down to 18Hz. The sub's new compact design keys are found in its application of B&W's long-standing expertise in ultra-strong, ultra-light KevlarÆ-based loudspeaker diaphragms, and in an leading-edge new amplifier design that is very small, very efficient, and very powerful.The ASW 2500's 10-inch driver effectively disguises its potential. A particularly strong blend of Kevlar and natural fibers results in benchmark stiffness. This allows the B&W design an extraordinarily long-throw action (for powerful deep bass from a small unit), and remarkable resistance to deformation (for very low distortion and coloration), despite the considerable stresses of both voice-coil action and small-enclosure internal pressures. Driven with ""enough"" power - no mean feat - in a properly aligned sealed-box enclosure, this unusual transducer can deliver virtually the same extension and bass quality as the firm's much admired and far larger 12- and even 15-inch systems. At the same time, the ASW 2500's small size and exceptionally low mass assure quick, transient-faithful bass reproduction.What constitutes ""enough"" power? According to the ASW 2500 design team, as much as 1000 watts - one kilowatt - of audio amplification. The ASW 2500's internal electronics employ a single, bass-optimized power amp channel with 1kW capability for transient low-frequency events. Like the unusual ASW 2500 driver, this was specifically engineered for the new B&W design. The amp's linear MOSFET output stage safely delivers very large current excursions while minimizing distortion, while its extremely efficient switching-mode power supply reduces both bulk and waste heat dramatically. This in turn permits the amplifier to fit within the ASW 2500's small enclosure, and removes the need for any external heat sinks. The ASW 2500's electronics also include a soft-limiting circuit that prevents any possibility of audible distortion, even under severe overdrive conditions.The ASW 2500's line-level inputs supply connection to the subwoofer output of any A/V receiver or preamp/processor, while dual line outputs permit use with preamp/power amp combos, and multiple subs; and incorporates an active second-order 80Hz high-pass filter for power-amp returns. In addition to continuously variable sub Volume and Lowpass Frequency controls, the compact B&W provides subwoofer phase reverse and lowpass filter-defeat switches for optimization in any placement and with any system, plus an EQ Contour A/B switch that adjusts the subwoofer's response for different placements, or for maximum extension or maximum output.The B&W ASW 2500 is finished in black ash and cherry vinyl woodgrain, with black cloth grille. The MSRP is $1,400, and the unit is now available.