Review: B&W DM-14 speakers
Originally printed in the February 1981 issue of Gramophone.
WE reviewed the B&W Model 801 professional monitor loudspeaker in January 1980 and that continues to be the company's flagship, scoring successes at home and abroad in professional and domestic circles. However any viable loudspeaker manufacturer must offer a range of systems, not neglecting the markets further down the price scale. Thus B&W have followed up the 801 (now £1,045 to £1,238-10 per pair) with a slimmer and less expensive 802 floor-standing monitor (£785.00 to £932.82), and applied their research to producing a mini-monitor, the DMI2 (£119.50 to £220.50).
The DM 14 may be regarded as a larger and more efficient version of the DM 12, though it is still of convenient bookshelf dimensions and has an internal volume of only about 1 cubic foot (28.32 litres). The drive units are similar to those of the DM 12 but the bass/midrange driver has been duplicated to produce a three-way system with the units mounted vertically in line. The TW26 high frequency driver has a 26mm diameter polyester weave dome with high-temperature voice coil and a total moving mass of only 0.3g. The two bass/midrange units have damped 150mm Bextrene cones, again with high-temperature coils on a foil-lined former. The lower unit is gently rolled off at 6dB/octave above 400Hz partially to produce the desired uniformity of directivity in the vertical plane in the lower registers, and also to preserve minimal phase shift. Crossover to the 1-IF driver occurs at 3kHz with third order slopes.
The network is more than usually elaborate, using close tolerance reversible electrolytic capacitors and ferrite-cored series inductors. There are 34 components in all, of which 22 are used in the overload protection circuitry. This B&W patented system is called APOC (Audio Powered Overload Circuit) and protects against high voltage transients, continuous input signals of high average power and spurious DC at the input. It is self-powered, from the audio signals, and so needs no battery. In the event of an overload condition, a red indicator at the bottom lefthand corner of the front grille lights up and the signal is attenuated—to be restored automatically when the overload condition ceases.
The DM14 is unusually heavy for its size, which is evidence of the robust construction. The enclosure is made of 12mm high-density particle board laminated with 6mm bituminous pads to damp panel resonances. The front baffle is of 19mm thick Medite and the grille cloth is stretched over a stable frame which fits over the baffle-board on rattle-proof press-studs. The sockets for cable connection are let into the recessed rear panel and are of a new spring-loaded slider type giving safe gripping of the bared wires.
While the small dimensions of this speaker will make it attractive for shelf mounting in confined spaces, the designers are naturally concerned at the possibilities of random reflections in such a case. The detailed instruction manual therefore contains advice on room acoustics and the proper location of the speakers for optimum results. It recommends a position at least 0.5m from walls and 0.2m above the floor. To this end, B&W market special stands Type STAV/14 (£30.19 per pair) which they regard as optimum for the DM14.
A pair of the stands was received with the review loudspeakers and the total effect is very neat and tidy. The stand base is beautifully veneered, as are the speakers, and the vertical column enamelled in a matching brown shade. The floor space occupied is really very small so that even quite small rooms should be able to accommodate a pair of these handsome speakers comfortably.
How it performed
Testing this loudspeaker produced one pleasurable experience after another. Sensitivity was higher than the average for small enclosed systems, allowing any reasonable hi-fl amplifier to be used. If one then tried to overload a pair of these DM14s by stepping up the input power, the music got steadily louder but without changing its character. Coward that I am, I could never bring myself to feed in music signals at a high enough level to trip the overload protection circuitry. I gave up trying when the acoustic level was very much louder in a normal-sized room than I considered reasonable. For domestic purposes, then, these speakers will take all you care to hand out—and deliver very musical sounds.
The smoothness of response over the middle and upper registers was also excellent. Plotting the response to one-third octave bands of pink noise, using a Bruel & Kjaer sound level meter, showed barely +IdB variation from about 200Hz right out to 14KHz, with only a gentle roll-off beyond this. This is quite exceptional: indeed the extended treble response does seek out any imperfections in the recorded signal. However, given good clean records or broadcasts, the detail and clarity of reproduction is very apparent. Switching between the DM14 and the B&W 801 naturally demonstrated the more emphatic bass of the latter, balanced perhaps by an even more analytical upper mid-range. Still these two B&W designs shared many virtues, and I would expect them both to stand out as top class reproducers in any showroom comparison with other speakers. With its modest dimensions, safe power handling and reasonable price the DM14 makes a very safe recommendation to discriminating purchasers.
Manufacturer: B&W Loudspeakers Ltd., Meadow Road, Worthing, West Sussex, BN11 2RX. Price: £275.00 per pair (Teak, Walnut or Black Ash), £314.29 (Rosewood).