B&W CM6 S2 Loudspeaker

Stand-Mount Winner

Equipment report
Bowers & Wilkins CM6 S2
B&W CM6 S2 Loudspeaker

There seems to be two camps of loudspeaker aficionados: those who swear by floorstanders, and those who swear by stand-mount speakers. I’ve been on both sides at various times in my life, mainly because of space—floorstanders go in large rooms, and stand-mount speakers go in small rooms, right? Floorstanders provide room-filling bass, while stand-mount speakers provide much better mid and high frequencies due to one less crossover point and reduced cabinet resonances, right?

Well, at least most people I talk with are of this impression. Now that I have a pretty large listening room, I was curious to test B&W’s new $2000 CM6 S2 stand-mount loudspeaker with B&W’s iconic “Tweeter on Top” technology. I listened to them extensively in my smaller listening room, but I was also curious to hear how they would perform in my main listening room, now that it has doubled in size. In short, they performed surprisingly well overall, and exceptionally in the mids and highs with a generous helping of low-end pleasure.

Setup and Design
Even though I have a large listening room, I settled on a setup with the speakers eleven feet apart, and four-and-a-half feet from the rear walls, with a 20-degree toe-in. I tried placing them as far apart as possible for maximum soundstage width, but despite the CM6 S2’s wide tweeter dispersion, imaging began to suffer after about fourteen feet. Keeping the CM6 S2s less than twelve feet apart with a listening position around ten feet kept the imaging tight and the soundstage immersive. My listening preference is to have extremely tight and accurate imaging; I can tolerate a bit of brightness or lack of low-end extension, but a diffuse, inaccurate, or smeared soundstage drives me nuts. Even in a live setting microphones can be bright and bass can overload the venue, but rarely—if ever—is “imaging,” as we know it, off. With the proper toe-in for your room—in my case 20 degrees—the CM6 S2s can provide both a wide soundstage and detailed imaging.

The one caveat about toe-in relative to listening-position distance with the CM6 S2s is brightness from the tweeter, which can be overpowering if you are sitting nearfield in a small room. With these speakers, I found a toe-in that aims the tweeters a little wider than the edges of your ears worked best to produce a wide, precise, and not-too-bright soundstage.

Surprisingly, the CM6 S2s are bi-amp capable, which I think would work best for those employing lower-powered tubed amplifiers. Although it’s great that these B&Ws can be bi-amped, I didn’t make much use of the provision in my listening tests. My tube amp produces 80W in triode, and 112W in ultralinear, and I preferred the sound of a single amp to that of two—at least with these speakers.

B&W’s iconic Tweeter on Top—more precisely described as a free-mounted, decoupled, double-dome aluminum tweeter—has been redesigned for the CM Series loudspeakers. The CM6 S2 is the only stand-mounted loudspeaker in the CM Series to employ the Tweeter on Top design, which is generally only found on its bigger—and more expensive—floorstanding siblings. So what’s the purpose of a tweeter housed in its own enclosure mounted atop the speaker? According to B&W, such a configuration isolates the tweeter from enclosure resonances, minimizes the diffraction of high frequencies by the enclosure, improves time-alignment with the midrange driver (and thereby reduces acoustic lobing), and allows fine-tuning of the tweeter itself.

The CM6 S2s have a sensitivity of 88dB and a nominal impedance of 8 ohms, which puts them right in the middle of the sensitivity range. I would recommend having at least 60W of amplification at your disposal, and preferably 100W. Remember, doubling amplifier power leads to a 3dB increase in SPL at 1m, so make sure you have enough juice if you like to crank it up every now and then, otherwise you could drive your amp to clipping, and that’s not good for your speakers, your amp, or your ears.