The CM10 stereo speakers from Bowers & Wilkins are very well built, highly specified and incorporate a number of technologies from the company’s even higher ranges. Stephen Dawson explains.

Large loudspeaker brands inevitably cover a fairly wide range of the market, else they would not be large. Some run from true entry level to somewhere in the middle of the quality possibilities. The English firm Bowers & Wilkins starts in the middle and goes right up into the inarguably high end 800 Diamond Series (priced at up to $29,000 for a stereo pair) and the Prestige series, with the $95,000 ‘Nautilus’ stereo speakers.

In the middle of B&W’s range – which means rather high end by the average punter’s standards, is the CM series, of which the CM10 stereo speakers are the top models.

Three ways
Perhaps befitting a company that has been around since soon after World War II, these are three-way loudspeakers, albeit with five drivers in each box. At the top – very prominently at the top – is a 25mm dual layer aluminium dome tweeter. The prominence is due to the tweeter being located in its own small, semi-teardrop-shaped enclosure atop the main enclosure. Each of these is fronted by a metal grille which can be removed if you wish to experiment with differences that this might make to sound quality. In theory, anyway. A small plastic forked device is provided to help support the tweeter enclosures during this process. I had a go on three occasions, but each time found it too difficult to do without risking damage, so I just left them in place.

The point of the dual aluminium layers – the underneath layer doesn’t cover the centre of the dome – is to allow fine tuning of the resonant behaviour at very high frequencies. The result: balanced output to 28,000Hz, and significant output all the way to 50,000Hz.

Beneath this, at the top of the loudspeaker enclosure proper, is the distinctive yellow of a woven Kevlar midrange driver. A rather large one at 150mm. An advantage of a larger diameter is a reduction in the need for wide excursions of the speaker cone. So rather than the usual rubber roll surround often employed with small midrange drivers or large bass/midrange ones, this driver is able to get away with foam surround, which B&W says allows a more piston-like performance. Unusually, the whole unit is ‘decoupled’ from the cabinet. That is, it is itself on a very stiff suspension system that helps isolate it from resonances generated in the cabinet by the three 165mm bass drivers.

This midrange driver handles the frequencies from 350 to 4,000Hz.

The cabinets are bass reflex loaded with a rear port. As is B&W’s usual practice, foam bungs are provided which can be put into the ports if your installation circumstances are such that the loudspeakers have to be placed closer to a wall than is optimal, leading to excessively strong bass. By closing off the ports in this way, the speakers can be turned into something approximating an infinite baffle design, with reduced output around what would otherwise be the port resonance.

The enclosures are extremely well built, as shown by the overall weight of each loudspeaker of 31kg. They stand very stably on the large, 25mm thick plinths packed with each of them, and into which supplied spikes can be fitted.

Electrically these speakers should be suitable for most systems. They are nominally rated at eight ohms, although B&W does note that there is a minimum impedance of 3.1Ω (the frequency of this isn’t specified). They are of slightly higher sensitivity than usual, producing 90dB for one watt input measured at a metre. B&W says that they are suitable for use with amplifiers rated at up to 300W of clean power.

The review speakers were beautifully finished in a black piano gloss, although other finishes are available.

Sound
I used this speaker pair very extensively indeed over more than a month. There were two primary configurations. One was as the left and front right stereo pair of a 5.1 system, with my regular high quality surround and centre channel speakers and a very powerful subwoofer. In this mode I used a high end home theatre receiver’s EQ facilities to ensure a good tonal match between all the speakers, and this was clearly successful, as evidenced by the precise sense of audible direction through a full 360 degree circle.

But mostly I used the speakers in Pure Direct stereo mode – with no EQ nor any other kind of sound processing – for listening to a wide range of CD or better quality stereo music. By ‘better quality’ I mean high definition content in DSD format, or PCM at 96kHz, 24 bit resolution. Plus I tossed in a bit of vinyl.

English loudspeakers have somewhat of a reputation – long had this reputation in fact, for decades – for producing a ‘mellow’ sound. If that might seem less than perfectly accurate, you’d be right. But it is very pleasant.

With these loudspeakers B&W seems to have moderated a desire for ‘pleasant’ sound in order to provide an extremely accurate sound. Which is music to my ears.

The result is that the loudspeakers are a little bit unforgiving, in that they expose weaknesses in some recordings, but also that they deliver pretty much everything in the signal, including all the good stuff that lesser speakers sometimes omit.

The Alban Berg Quartett recording of Schubert’s String Quintet (they added Heinrich Schiff on a second cello for the occasion) was delivered with gusto, and no diminution of the bite of the strings. A ‘mellow’ speaker can smooth the texture a touch. These B&W speakers instead made them sound as they are in real life, with the direct sound from the vibrating strings empowered by the resonances of the instruments’ bodies, not overpowered by them.

Yet neither were they made harsh or difficult to enjoy. The stereo sound stage delivered by these speakers was also impressive with this, with depth in the stage, and height and a clear sense of the precise location of each instrument, along with a feeling of air around each of them.

Full symphony orchestras were handled without the confusion that can sometimes muddle clarity in climactic sections. ‘The Great Gates of Kiev’ at the end of Mussorgsky’s Pictures at an Exhibition were delivered without any apparent compression of the dynamic peaks, and with impeccable coherence. The Schedrin percussive orchestration of Bizet’s Carmen, as delivered on the magnificent Chandos recording, was wonderful in the way that as peaks approached, my anticipation of their punches being pulled was repeated foiled as they thrust out, seemingly unlimited in power.

But they were equally good with modern music. With Primus’ Tales from the Punchbowl the strings of Les Claypool’s bass had all the bite you could want, with the bass content wonderfully powerful and coherent, while the drums punched through with – again – no apparent dynamic compression. The complex rhythmic lines were easy to follow even at very high playback levels. Primus, for all its wildness, is recorded with excellent control so that on a good system there is a sense of silence surrounding each instrument, and that in turn allows air. These loudspeakers were up to the task of rendering all that close to perfectly.

Prefer something a little more pop-like? Beyoncé is typically recorded fairly brightly, with there being the danger of a painful sibilance on some notes. With, that is, so-so loudspeakers. With these B&W speakers her voice was conveyed with accuracy – the brightness intact, but without painful resonances or peaks – with the surprisingly complex accompaniment being fully realised

Conclusion
B&W loudspeakers are available in a quality range from pretty high to stratospheric. If the CM10 series fall within your purchasing criteria, it’s hard to see how you could in any way be disappointed by them.