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B&W CM8 Floorstanding Loudspeaker Listening Tests

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Initial Impressions

Tonally, the thing that strikes you upon first listening is the overall neutrality and understated quality to the sound. These are not speakers that are going to reach out and grab you with low-end drama or high-end sizzle. Sophisticated, experienced listeners will recognize their accuracy and lack of coloration right away; less experienced listeners—perhaps wanting a bit more impact and emotion—may be somewhat disappointed.

The bass is particularly interesting. First off, it is a superbly-executed bass reflex design. The two relatively small 5” woofers working in tandem deliver some pretty weighty bass and bottom to virtually any program material. The bass detail is excellent: The clichéd description of “hearing the rosin on the bow” is perfectly apt here. Never is there even the slightest sense of overhang or “slowness” to the bass. It is crisp and agile at all times. B&W’s LF spec of -3dB @ 69 Hz is probably the most honest—even overly-conservative—bass rating for an expensive loudspeaker I can ever remember seeing. Most manufacturers would rate an $1100 speaker as reaching down into the mid-50s Hz, at least. 69 Hz is more like a compact bookshelf LF rating than a floorstander. But the CM8 never sounded bass-shy on any material and the bass quality was extraordinary in every respect.

Which brings us to the next subject: those foam bass plugs. As stated before, these are a two-part cylindrical foam “plug” that fit into the rear bass Flowport™. You can effectively transform the CM8 into a sealed system by using the entire plug, or you can remove the center section of the plug and get a quasi-combination of sealed and ported performance. As shown in the manual, using the plugs reduces the bass output (a higher 3 dB down point) and makes the LF rolloff more shallow. Using the full plug makes the CM8 behave like a sealed system, with a 12 dB/oct rolloff and a higher 3 dB down point than when the port is fully open.

Why would anyone want to do this? The low end of the speaker is so correctly engineered and clean-sounding as a bass reflex system that to arbitrarily change it into something non-optimal seems idiotic. About the only worthwhile use I can see is to change the CM8’s LF rolloff to 12 dB/oct to match up with THX-spec pre-amps when using a subwoofer. THX specifies that the “satellite” speakers have a 2nd-order rolloff (12 dB/oct) to combine properly with the 2nd-order LP on the subwoofer. But for full-range music use, as I was using them, the port plugs served no useful purpose whatsoever.

The tweeter is a 1” aluminum dome with the famous B&W tapered Nautilus-type rear chamber behind it. The high frequencies of the CM8s were consistently smooth, with nice detail and “shimmer,” and a strong sense of three-dimensionality. Triangles and other high-pitched percussive effects seemed to hang in the air, as if the listener could visualize the instruments in real space. Some listeners have a negative pre-disposition to metal domes, thinking they will sound harsh or metallic. Whether due to the damped, tapered rear chamber or simply due to intelligent crossover design and sane voicing choices, I could find no basis for aural criticism of the CM8s highs.

The midrange is reproduced by B&W’s Kevlar FST™ 5” driver, which uses essentially no surround, so as to keep the cone straight and pistonic in its action, in contrast to the cone’s tendency to “flop’ and move in a non-linear fashion when it has a big, overly-compliant surround. Since midrange drivers do not have to move long distances (unlike woofers, which need to have very long excursion to reproduce ultra-low frequencies), there is no actual need for a large, compliant surround on a midrange driver, according to B&W’s engineers, and in their view it is a detriment to accurate midrange driver motion. Hence the rationale behind the Fixed Suspension Transducer, or FST™.

The CM8’s midrange is indeed detailed and non-fatiguing, and it could play quite loud without obvious distress. How much of this agreeable character is directly attributable to th

e specifics of the FST design is open to question. The mids did seem to exhibit a very slight “papery” or nasal quality, however. I suspect this is more of a voicing choice or from crossover design than because of the midrange driver’s surround design per se. But compared to my reference speakers, there was a slight, but constant, amount of midrange coloration. It was never objectionable and never noticeable, except on a direct A-B comparison.

Listening Tests

I have used many of the same discs for many years to test loudspeakers, not simply because they’re well-recorded CDs, but because I know them so well that they are reliable test devices that I can compare from speaker to speaker and be confident of the differences I’m hearing.

CD: Donald Fagan—The Nightfly

fagan.jpgA nicely-recorded pop CD, with Fagan’s/Steely Dan’s trademark clarity, solid deep bass and crisply-etched vocals. The CM8s presented the cuts with transparency and excitement, accompanied by a strong, clean bass line. There are some very deep bass tones on The Goodbye Look, which the CM8 (rated with unusual honesty down to just 69 Hz @ -3dB) pretty much only hints at, but that was to be expected.

CD: Jennifer Warnes—The Hunter

This is an over-played, over-used, totally synthetic-sounding and too-heavily processed pop recording. But the opening cut, Rock You Gently, is so chock full of quantifiable, repeatable audio tidbits that if one overlooks the questionable musical merits of the song, its sonic traits do provide some valuable information. The recording has a very deep, strong bass line throughout and some sharp snare drum <cracks> that punctuate the background. But it’s at the 2:33 mark of the track that things get interesting. I’d used this cut for years to test how well a speaker can simultaneously deliver clean, low-distortion deep bass (long excursion), while keeping the female vocals clear and preserving detailed highs. It’s a tough test for most speakers. And if a speaker doesn’t have subterranean bass response on its own, it’s a good test to see how well the speaker will ignore the very deepest bass that it can’t reproduce anyway while still doing a good job with the rest of the spectrum. I’d gone years listening to this cut on all the speakers I’ve voiced without realizing that at 2:33 there is a sustained low-20’s Hz tone (about three seconds long) that just rises up from the floor and absolutely dominates the room. Very few full-range speakers will reproduce this tone, since most full-range speakers—even quite excellent, expensive ones—will only respond, honestly, down to 35-40 Hz or so. (My reference speakers are sealed systems with dual 12” woofers (with a very shallow 12 dB/oct rolloff), rated very realistically down to -3 @ 28 Hz. With a little room gain by virtue of being within a foot of the wall behind them (per the manufacturer’s recommendation) they are quite flat in my room down to the lower 20’s. At the 2:33 mark of this cut, fed with 400 distortion-free watts, they make dogs cower and babies cry.

To the CM8’s everlasting credit, at 2:33, they dutifully ignore this 22 Hz tone and simply continue their clear, unruffled response, without missing a beat or showing any signs of distress whatsoever. I am as impressed by what they don’t do here as I am by what they do.

CD: Kurt Elling—Dedicated to You

elling dedicated.jpgThis is a superb live recording of jazz vocalist Kurt Elling backed by a big band featuring Ernie Watts on tenor sax and Lawrence Hobgood on piano. The first track—All or Nothing at All—starts off with a string quartet intro, beautifully recorded. Played on top-flight equipment, it is almost believable that a string quartet is, in fact, right there. After that intro, there is a piano run ending in a single very high note, struck quite hard. It’s a great test of a tweeter’s power handling and ability to project a three-dimensional, organic sound into the room without being ‘spitty’ or ‘hissy.’ The B&Ws shined here, and their highs were as solid and well-reproduced as one could ask for.

Elling has a great voice, deep and resonant, with tremendous range, power and control. He is a master vocal stylist and his ability to go anywhere he wants and always return home is without equal among today’s singers. If you’ve ever seen him live, you know how he quickly captures the audience’s attention, gains their complete confidence that he’s in total musical command, and then takes them along for the ride. This recording is mixed with Elling in a very solid center image, and the CM8s convey that without equivocation. Elling is front and center, and the band is behind him and wide to each side. In spite of their 69 Hz bass rating, there was never a time when the sound was thin or lacking in any way. Instantaneous A-B switches to my reference speakers revealed that deeper sound was there to be had on the recording, but listening to the CM8s alone never left you feeling as if something was missing.

CD: Ariel Ramirez/José Carreras—Misa Criolla

misa criolla.jpgWonderful Phillips recording of classical/vocal music, the first two cuts really test a speaker’s ability to resolve low-level detail and present a three-dimensional sonic landscape. Carreras’ voice is pure and delicate, and is accompanied by very subtle tympani strokes in the background. Properly reproduced, these strokes convey a sense of the mallet head hitting the drumhead and the resonant tail from the strike carries on long and quietly fades off behind the vocal. The CM8 proved up to the task of speaking quietly, but with precision and authority. Lesser speakers smear these details together; the B&Ws kept things clearly delineated and focused, but without artificial hype or an exaggerated top end. This is a tough test disc, highly recommended.

Diane Shuur & The Count Basie Orchestra

The first cut—Deedles’ Blues—is a rollicking, gutsy, full-blooded big band jazz vocal. Ms. Shuur’s voice is not exactly cut from the Cloth of Subtlety, if you catch my drift. And since this is a GRP recording, everything is just a bit overdone, a little larger than life. On second-tier equipment, things can degenerate into a screamfest pretty quickly, prompting a hurried lunge to turn down the volume control. First-rate gear presents this cut with lifelike verve and excitement, not with harshness and edginess. The CM8 handled this very well, although the aforementioned trace of midrange nasality just poked its head above the horizon on Shuur’s vocals at very high SPLs.

 

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Recent Forum Posts:

ratso posts on August 04, 2012 08:48
nice review, and yes it is nice to see some of the bigger names being reviewed here. but… i hate to say this, because it could open a big nasty can of worms. but the next time can we omit the word “chinese” being used in a derogatory way here? you could have just told us “there is good mdf and bad mdf”, etc.
AcuDefTechGuy posts on August 03, 2012 10:44
Just more info:

CM8
Cartons = $54 each speaker
FST midrange = $123 each driver
Tweeter = $147 each driver
Woofers = $ 71 each driver
Plinth (body) = $117 each speaker
Crossovers = $163 each speaker
Grilles = $100 each speaker

And yes, very nice to see more reviews of the big brands.
Nuance AH posts on August 03, 2012 08:54
No measurements?
templemaners posts on August 02, 2012 14:30
I tried 2 different browsers and 2 different computers, but didn't see the jump to bar on the Intro page, but it showed up on the listening and conclusion pages Matt put up.

Thanks for the links.

Side note on the actual speakers - the press photos make them look a lot wider than 6.5".
gene posts on August 02, 2012 14:26
templemaners, post: 898390
I don't see anything of the review past the introduction page.

anytime we change the publish date and post, it takes an hour or so for the page to cache out and show the other pages. It should appear, soon.
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