At the top of the B&W Loudspeakers product list are some exotic and trail-blazing models: we think immediately of the Matrix 801, chosen as monitors by many professional recording engineers, and the curiously shaped but sonically outstanding Nautilus. Innovations researched and developed for these flagship loud-speakers have a way of gravitating down through the rest of the B&W ranges so that its Matrix technique of reinforcing panel rigidity with a honeycomb structure within the cabinet, for example, can be found enhancing the performance of loudspeakers at quite modest prices.
This brand new DM302 budget baby, costing only £129-99 per pair, somehow reverses the ‘top model downwards’ process. Conceived as a deliberate bid for the under-£200 market, which B&W has identified as representing 50 per cent or all UK loudspeaker sales totalling about 250,000 pairs annually, the DM302 nevertheless features a totally new design idea called the Prism system. B&W is so pleased with the results that it has applied for a patent and we may expect to see it percolate to models further up the price scale.
It seems that the designers were looking at ways to tackle two of the prime problems in box loudspeakers - panel resonances and the build-up of internal standing waves by reflection between the parallel walls. They thought of roughening the inner surface of the back panel and then took this idea to the ultimate by introducing many tapered pyramid shapes which extend into the cabinet, in imitation of the absorbent wedges which traditionally line all the wall surfaces in anechoic test chambers.
Though the wedges used here are of hard plastic rather than soft absorbent material, they will certainly break up incident sound waves radiated from the back of the loudspeaker cone. Making the wedges of different lengths has spread the frequency of maximum effect, and the wave scattering will not Only inhibit standing waves but also increase the number of reflections and dissipate energy faster.
None of this would have been possible without the latest injection moulding techniques which can cast the whole back panel in one piece. In fact the wedges are hollow, as can be seen from the back of the cabinet, which looks like a rectangular honeycomb of 39 square holes of varying depths, plus the larger recess for the output terminals. The structure is further strengthened by six horizontal braces between the front and back panels, and there is a layer or absorbent foam strategically placed to damp the randomized reflections.
The front panel too is a high-quality injection moulding, rounded for smoother edge diffraction, with the two drive units damped to the inner surface. The 26mm soft dome tweeter has a contoured low-diffraction face plate while the 130mm bass/midrange unit has a doped homogeneous fibre cone with nitrile rubber surround mounted in a pressed-steel chassis. The enclosure is bass reflex loaded with a slotted port across the bottom of the front baffle, clear of the removable grille which is again a plastics moulding and curved to fit the baffle. The crossover frequency is set at 3kHz and the network of high quality components, including both P-core and air-core Inductors, is wired to the back of the terminal block. The terminals themselves are multi-purpose and will accept wire, spade connectors or 4mm plugs, although the 4mm sockets are supplied with coloured plastic blanking plugs in accordance with EU safety regulations.
To succeed in the budget marketplace, a loudspeaker must present an easily driven load for quite low-powered amplifiers (as well as more powerful ones). To this end the DM302 has the standard 8 ohms nominal impedance and surprisingly high sensitivity (91dB) considering the system’s small dimensions. The cabinet is covered in vinyl veneer with a black ash finish. The drive unit magnets are not shielded so the DM302 is not suitable for placing very close to a television or computer monitor screen.
Performance
Despite their innovatory Prism technology, the designers of the DM302 have not opted for an overbright or ear-catching overall balance. High frequencies do extend to the upper limits of hearing but without emphasis. Similarly the bass end has been allowed to roll off as we might expect from a loudspeaker of this size. There is no resonant one-note bass effect, which is sometimes heard when designers have tried to introduce a false bass extension. The new cabinet construction and the extra front-to-back braces are obviously succeeding in keeping box-like resonances 10 a minimum.
‘Smoothness’ perhaps sums up one’s overall impression and of course is a characteristic well suited to the reproduction of classical music of all kinds. There is also a calculated evenness of high-frequency dispersion in the horizontal plane. This feature is not often quoted in figures but the B&W specification does claim a response within 2dB of that on the reference axis over a 46 degrees arc (10 degrees in the vertical plane) and I was able to confirm this claim. The audible benefits are a well-filled stereo stage in the space between the loudspeakers and a fairly wide listening area over which the L/R balance is properly maintained.
All the same, I found it helpful to toe the loudspeakers inwards slightly to provide maximum treble, and I removed the grilles for the same reason after ensuring that the soft dome of the tweeter would be in no danger from sharp objects. Applying the highest critical standard, which is probably unfair in a review of a budget loudspeaker, I did identify a certain lack of presence and muddling in the lower midrange area, so important for the natural reproduction or male speech, piano tone, etc.
On the positive side, there was fast attack and the relatively high sensitivity made it easy to produce good clean dynamics in an average-sized room. Going into overdrive is not recommended: I found that sound quality began to glare at about the level where my ears were in any case beginning to object.
As an entry point’ model the DM302 will comfortably outperform the excessively bass-shy ‘shriekers’ so often supplied as part of budget systems. It does a good job of smoothly reproducing the sounds of music, a better job indeed than we have any right to expect for £130, and should encourage many a newcomer to set out on the adventure trail that leads to true high fidelity.