Why would a manufacturer want to change a perfectly good speaker line? It could be to incorporate a new technology or some ingenious design twist; but, in the case of the Bowers & Wilkins' recently updated CM Series, it looks to me like the reason boils down to screws.
The previous version of B&W's CM1 mini-monitor had a total of 10 screws on its front baffle: six to hold the woofer and four more to secure the tweeter. That was perfectly fine 10 years ago because almost every speaker had screws on the front then. However, more and more speaker companies are following Apple's lead and eliminating most or all of the visible fasteners on their products. The new B&W CM1 S2 has a few small screws visible on the back, but none on the front. The new design also eliminates some of the metal accents that tarted up the old CM1's front baffle. It's now an elegant-looking little speaker, whether it's wearing a satin white, gloss black, or rosenut finish.
There is some new technology in the CM1 S2, most notably the double dome decoupled tweeter. The tweeter's dome is like two laminated aluminum domes with the center of the rear dome cut out. The result is a diaphragm that's much stiffer around the edges, where it receives all the force from the voice coil, yet only a little heavier than a conventional aluminum dome. This should result in lower distortion - and it should shift what distortion there is up to higher and less audible frequencies. A ring of gel decouples the tweeter assembly from the speaker cabinet, so it's affected less by the much more powerful vibrations of the woofer.
Like most of the tweeters in B&W's speakers, this one has a Nautilus tube: a long, tapered tube on the back that absorbs all of the sound waves coming off the back of the aluminum dome so that the sound waves can't affect the operation of the dome or "leak through" the diaphragm. This is the same principle by which transmission-line speaker cabinets work, and in my experience it works very, very well.
The midrange/woofer uses the same design B&W's been working with for a while, with a yellow woven Kevlar diaphragm that was chosen because of the fiber's extreme tensile strength, designed to provide a smooth, articulate midrange and distortion-free bass. The back panel has a port for the midrange/woofer and dual metal binding posts. A magnetically attached fabric grille is included.
At $1,100 per pair, the CM1 S2 is the least expensive speaker in the revised CM line, which includes two other bookshelf models, three towers (including the CM10 and CM6 S2 that we previously reviewed), two centers, a surround, and a subwoofer.
I placed each CM1 S2 atop one of my Target metal stands, each of which is filled with kitty litter to give it more weight and prevent the metal from ringing. I used Blu-Tak poster adhesive to secure them to the stands.
The back corner of each speaker sat 26 inches from the wall behind it. This gave me a reasonable amount of bass, at least for a mini-monitor. I tried pushing the speakers back closer to the wall to reinforce the bass, but this action tended to make the bass sound excessively punchy, probably because it emphasized the rear port's resonant peak. Because these speakers don't produce a lot of bass, they're easy to position; the more bass a speaker has, the more its performance is affected by room acoustics.
I used my usual system for the review: a Krell S-300i integrated amp, fed signals from a Sony PHA-2 USB headphone amp/DAC connected to the Toshiba laptop on which I store most of my music. I also used a Music Hall Ikura turntable routed through an NAD PP-3 phono preamp.
The grilles had almost no audible effect. I left them off because the speakers looked so much better that way.
Mini-speakers have a rep for open sound, a broad soundstage, and precise imaging. That's for two reasons: 1) because the enclosures are narrow, the diffraction off their side corners isn't so troublesome; and 2) because many mini-speakers use small woofers, which have broader dispersion at high frequencies than large woofers do. Of course, this is just generalizing. There's no reason a tower speaker can't have these traits, which is why I hate it when I audiophiles assume mini-speakers have better spatial characteristics. Sadly for me, the CM1 S2 will only encourage such generalizations.
This little speaker produces such a spacious soundstage, and such realistic imaging, that I'd almost consider it a must-hear for anyone just getting interested in audio. Speakers shouldn't sound like their sound is coming from a box. They should sound like the sound just appeared in space in front of you...and that's what the CM1 S2 sounds like.
"Very very very good," I noted when I played "Midnight Voyage" from saxophonist Michael Brecker's now-classic Tales From the Hudson. I found it hard to decide whether I was more impressed by the CM1 S2's reproduction of the tenor sax, the guitar, the piano, or the drums. That's because the timbre of the speaker accurately portrayed every instrument without favoring any.
I guess I'd have to say it was the drums in "Midnight Voyage" that really killed me. The little B&W has a way of imaging cymbals, in particular, that sounds incredibly real. You can hear the precise placement of each cymbal in the kit; many lesser speakers portray multiple cymbals as more of a formless wash of high-frequency energy. Accurate cymbal imaging is especially important because, in many recordings, the only real stereo information is from the stereo mics placed over the drum kit. Most of the other instruments are usually recorded with a single microphone and "steered" to a certain place in the stereo soundstage using the left/right pan controls on the recording mixer or in ProTools.
After hearing what the CM1 S2 did with "Midnight Voyage," I couldn't resist putting on another sax player: altoist Kenny Garrett playing "Sing a Song of Song" from the Songbook CD. And again, as real as the sax and piano sounded, it was the drums that blew me away. Not just the cymbals this time, either. I loved the way the CM1 S2's little five-inch woofer captured the punch and precision of the smaller kick drum that jazz players (in this case, Jeff "Tain" Watts) use instead of the big sonic cannons most rock drummers prefer. The dynamics of Watts' cymbals and rimshots also came through remarkably well, thanks to that double-dome tweeter, I suppose.
One of my favorite stereo soundstaging tests is Adrian Belew's "May 1, 1990" from the album titled Here. In this tune, Below resorts to all sorts of sonic trickery, such as panning a ticking clock around in the intro and playing with the width of his voice and an acoustic piano by mixing them hard-center then blowing them out to fill the room. (It probably seems stupid when you read about it, but the tune has a fantastic groove, and the effects play into the emotional content of the song.) The CM1 S2 completely blew me away with the way it filled the room on this tune. It reminded me of the spacious sound I've heard from dipole panel speakers like MartinLogans and Magnepans, but with more precise, pinpoint imaging than those speakers can deliver.
The CM1 S2 is no heavy rock speaker - and we'll get to that shortly - but I have to say I found it incredibly involving when I played "Highway Star" from Deep Purple's live album Made in Japan. Made in Japan was recorded in a quaint era when live rock recordings included some of the ambience of the venue itself, especially at the beginning of the opening tune, "Highway Star." Through the CM1 S2, I could clearly hear Ian Paice's snare drum echoing off the walls of Osaka Festival Hall as he prods the band into the tune. As the volume rose, I was amazed to hear how clearly and cleanly the CM1 S2 reproduced Ian Gillan's voice, even during his epic screams in the chorus. Although there wasn't much bass, I found myself furiously tapping my foot anyway.
Click over to Page Two for Measurements, The Downside, Comparison & Competition, and Conclusion...