B&W CM Series surround speaker system Page 2
With no bungs in their ports, in every configuration the B&W CM system sounded too rich and midbass-heavy, which is what I expected from the speakers' placements close to the rear wall combined with the inherently warm sound of my living room. With one bung in each of the three front speakers there remained a gentle but unmistakable midbass bump and a slight midrange emphasis, but both of these produced a pleasant warm glow without adding flab or annoying boxy colorations. Two bungs in each CM 4 yielded a too-thin sound, so I went back to one. The surrounds went bungless.
If you like fast, detailed, rhythmically supple, edge-of-your-seat sound, the CM system will not be your cup of tea. If you like the traditional warm, relaxed, midrange-prominent "British" sound, you'll appreciate the CM's comfortable, refined performance with a wide variety of music and cinema source material, though the top end was hardly polite in the British tradition. Bass was reasonably well-controlled, but I've heard tighter and better-defined low-frequency response—at higher prices, of course. The CM system had satisfying low-end heft for music with the front L/R speakers run full-range, but you'll need a subwoofer to feel the ".1" channel embedded in film soundtracks.
The system's midbass/midrange prominence was craftily counterbalanced by a lift in the presence region and a bit of sparkle on top. For this kind of money you can't expect miracles from a tweeter, and the 1-inch aluminum-alloy dome delivered none. The tweeter sounded somewhat fizzy on sibilants when compared with tweeters found in, admittedly, far more expensive speakers. This gave away the speakers' positions, though that could also have been due to the large bass-midrange driver working at the top of its high (4kHz) bandpass.
The warmth below, the bit of sibilant fizz, and the mildly uneven response at and above the 4kHz crossover—especially, I suspect, off-axis—gave the CM 4 (and, in 2- and 5-channel modes, the system as a whole) an identifiable character. But in its overall balance and freedom from serious colorations, the CM 4 was a winner. Unless your obsession is pulling apart and analyzing what you're hearing (my job description), you'll find the CM 4 easy on the ears but compelling enough to hold your attention.
Using the same tweeter all around, very similar midbass drivers in the center, identical ones in the surround channels, and the tweeters' subjectively wide dispersion, one might predict that the CM system would create a coherent 3-dimensional "bubble" of surround sound. That's what I heard. I usually find that well-designed, medium-priced systems like this that sound good in 2-channel mode spring to life with multichannel source material. That, too, proved true with the CMs, especially because its surround speakers are far more than the afterthoughts they are in some other systems. DTS surround music-only discs and multichannel SACDs were particularly well served by the rich, full-bodied CM system.
Probably due to its 21/2-way crossover scheme, the CM C center-channel didn't exhibit the typical lobing frequency suckouts you hear from many center speakers as you move laterally across the front. The CM C's overall tonality was reasonably natural and believable on dialogue, avoiding the chestiness that decreases intelligibility, as well as an emasculating midbass thinness. Still, the CM C's fine performance was somewhat marred by occasional minor sibilant hash that was probably due to an uneven off-axis response.
Movies vs. Music
Because of a bit of lift in the presence region, the musical CM system generated enough excitement on top to be effective as a home-theater system. But don't confuse "lift" with "sizzle"—the B&Ws didn't sound edgy or bright, but were capable of providing "snap" on fast-transient sound effects. The system also managed to maintain its tonal character and fine macrodynamic performance at high SPLs. When I cranked up the CMs on sound-effects-heavy movies, the words "polite" and "restrained" didn't come to mind. I auditioned some of Tron's effects-laden sequences and the system delivered them effectively.
Engineer Shawn Murphy's recording of John Barry's music for Dances With Wolves is one of the best-recorded soundtrack scores, especially on the DTS edition of the film, and through the CM system it was warm, rich, and pleasing. And with other recordings and films, while I've heard speakers with tighter, punchier bass, the CMs reproduced kick drums and standup bass with sufficient accuracy and rhythmic thrust to drive music and explosions forward to their intended destinations.
One concern: Though the CM system's efficiencies are reasonably high (rated at 90dB for the CM 4, 89dB for the CM C and CM 2), the specified impedance minima of 4.4ohms for the CM 4 and, especially, 3.6ohms for the CM C and CM 2, might prove difficult loads to drive for the inexpensive receivers typically used with systems at this price point. The measurements will provide more specifics.
Toward the end of the audition period, I drove each of the five CM speakers with a Musical Fidelity M-250 monoblock amplifier ($1200 each) placed within 1.5 feet of the speaker. This allowed me to use very short speaker cables and long interconnects—the opposite of what you can do with receivers. So configured, the system's bass tightened noticeably, and became much more defined and rhythmically lithe. Chances are that consumers considering the CM system will not be driving it with $6000 worth of monoblocks, but a carefully located spare stereo amp might punch up the overall performance considerably.
The key to a good, reasonably priced system is overall sonic balance, and in that department B&W's CM system was a complete success. Back off the analytical listening, and the CMs provided a rich, warm, inviting sound, with just enough sparkle on top to keep from sounding dull or plodding. Thanks to the fine performance from the surround speakers, the system created a big, billowy, 3-dimensional multichannel picture with plenty of air and ambience. There are probably some other systems for the same money that can offer flatter frequency response within a more limited frequency range, and punchier, more exciting sound. If you insist on those, and if you're looking for a soundtrack system as opposed to one that will do double duty as a music system, the CM system might not be for you.
But when you consider its reasonable price, sonic performance, superior appearance, and fit'n'finish, the B&W CM Series is a mighty attractive package that I'm sure will find a happy home in many living-room home-theater systems.