B&W CM8 Floorstanding Speaker System Review

B&W; CM8 Floorstanding Loudspeaker Introduction

B&W is one of the oldest and most respected speaker companies in the world. They have earned a well-deserved reputation for speakers that sound superb, feature innovative engineering, and utilize the highest quality materials for great cosmetics and fit-‘n-finish.

Designed in the UK and manufactured in China, the CM8 is a compact floorstander in their midrange CM family, just ahead of the 600 series, but beneath the 800 Diamond series. There are CM1 and CM5 bookshelf speakers, two CM Centres (love that British spelling!), two CM subwoofers and a CM9 floorstander above the CM8. At $1099 each, the CM8 certainly can’t be considered inexpensive, but just based on the quality of the materials and workmanship; they appear to more than justify their asking price.

At around 38” tall and only 6.5 “ wide with a very conventional rectangular cabinet shape, these speakers do not attract a lot of visual attention in the room. They’re quite innocuous and I doubt their visual presence would trigger the dreaded WAF to any significant degree.

Design Overview

The B&W CM8s were single boxed in heavy-duty corrugated and had high-quality EPS foam caps holding the speaker at each end of the carton. Chinese packing material is interesting: Regardless of the so-called “burst rating” printed on the corrugated carton or what kind of internal foam packing material they claim it is, in order to get the “good stuff,” a manufacturer has to pay a Chinese vendor top dollar. These cartons were burst rated at 300 lbs. Generally, Chinese cartons rated below 200 lbs. burst are made out of what manufacturers derisively call “cheese paper,” flimsy, lightweight material that seems ready to disintegrate under the slightest stress.

 

B&W CM8 Box Burst Rating Marking

Likewise, the internal foam packaging falls into two broad categories: 1) the cheap kind, that breaks into pieces and crumbles into tiny foam sawdust balls that float annoyingly all around the room, rendering impossible any thought of repacking with the foam inserts, and 2) the good foam, which stays together and makes repacking easy and repeatable.

B&W uses very high quality packaging. Having been involved in the design, sourcing and manufacturing of consumer electronics products for decades, I know the cost difference between good and bad materials, and what that says about what a given manufacturer thinks of their products and the image and impression they wish to convey to their customers.

This was a good first step.

The grilles were shipped in their own bag and the speakers themselves have a protective clear plastic shield placed over the baffle board to protect the delicate drivers during shipping and removal from the carton/initial setup. This is incredibly thoughtful and sensible packaging design. I have seen many a tweeter dome ruined by wandering fingers as the speaker was grabbed and carelessly pulled out of its box.

B&W CM8 Protector & Bag Covering Speaker

The speaker’s base (or “plinth,” as the Brits so amusingly call them) and the carpet spikes/rubber feet for hardwood floors sat in voids in one of the internal foam endcaps. The spikes/feet themselves were in a cardboard/plastic container, much like a small product you’d find at the store. Everything neat, everything nicely situated.

B&W CM8 Accessories

The plinth attached easily to the bottom of the speaker with the included machine bolts and hex wrench. Everything lined up correctly, and there was no paint of other obstruction to bind up the threads as the bolts were tightened.

There was another accessory that was unexpected: This was 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. The owner’s manual shows all three response curves: unplugged, partial plug, and fully plugged. More on how these sounded later.

 

B&W CM8 Foam Port Plugs

The CM8 might be compact at 38” tall x 6.5” wide, but it’s very heavy for its size and conveys a very solid impression to the user. There are two sets of binding posts—just below the dimpled port, as part of a common plastic assembly— connected by a brass strap. The ends of the posts have the required plastic plugs (a CE requirement), but these can be pried out if you want to use banana plugs instead of bare wire to connect the speaker wire to the posts. The posts themselves have a nice-sized hole to accept bare wire and that’s how I connected them with 14-ga wire. Nice, easy, and secure. I did not use the bi-amp feature, but it’s nice to know the option exists.

 

B&W CM8 Binding Posts

The cabinet itself was made of high-quality 7/8” MDF. (Again, not all Chinese MDF is created equal—there is “good,” solid Chinese MDF and there is flaky, cheap Chinese MDF. This was the “good” kind.) The driver areas on the baffle were routed out, so those sections are thinner than the rest of the cabinet walls, unfortunately. However, as can be seen in the photos, the inside of the cabinet has extensive windowpane bracing, which contributes to the cabinet’s overall solidity. The FST™ midrange driver is in its own isolated chamber within the cabinet. The cabinet is also stuffed pretty densely with a fiberglass-ish material throughout, no doubt with the intent of reducing internal cabinet resonances and standing waves to a minimum. One gets the overall impression that this is a very inert cabinet that does not negatively intrude on the speaker’s sound.

      

B&W CM8 Internal Views of Cabinet Bracing & Stuffing

This is a very attractive speaker with the grilles off. The silver “aluminum” rings around the woofer and the “aluminum” faceplate on the tweeter are actually just a thin (perhaps 2 mm thick) brushed aluminum flashing, adhered to a molded plastic substrate. This is pretty common practice among speaker manufacturers, as it gives them the opportunity to present nice-looking drivers that appear to have very expensive aluminum frames or faceplates, while keeping costs dramatically lower.

 

B&W CM8 Driver MR Trim Ring

In B&W’s case, however, these are, in fact, aluminum-frame woofer and midrange drivers. Once the trim rings are removed, you can see the raw drivers themselves: they have heavy cast aluminum frames, far stronger and less prone to ringing than cheaper stamped-steel frames.

 

B&W CM8 Midrange Driver

The woofers have vented voice coils, and measure 29 mm across, or 1 1/8”. This is a beefy voice coil for a small 5” woofer. A slightly larger voice coil like this will exert more control over the woofer’s cone for lower distortion and will handle a good deal more power than a conventional 1” coil, which is 27% smaller than a 1 1/8” coil. Nice design.

Also clearly visible is the unexpectedly large magnet structure, which no doubt contributes to a respectable overall system sensitivity of 88 dB.

 

B&W CM8 Bass Driver (notice the vents on the voice coil)

One small nit to pick with B&W, however (and to be fair, they are certainly not alone in this): There is a sticker on the back of each woofer magnet that clearly says “8Ω.” Since the two woofers are driven in parallel, that means the woofer section is 4Ω. The midrange and tweeter also carry “4Ω” markings on the back. This is obviously, intentionally, a 4Ω system, in spite of the factory’s specs saying “8Ω.” Many other speaker companies stretch the truth about their impedances also, because most less-expensive receivers can’t handle speaker impedances below 8Ω, and to publicize a low system impedance (4Ω) is to limit the speaker’s acceptability in the customer’s mind. One would logically think that a speaker of the CM8’s quality will be teamed up with amplification that can handle an under-8Ω load, but B&W is certainly not alone in bending the ratings rules here.

 

B&W CM8 Woofer Magnet

The distinctive yellow-woven B&W Kevlar 5” midrange driver features B&W’s proprietary FST™ design, which stands for Fixed Surround Transducer. According to the manufacturer, the FST design reduces the non-linearity in the driver’s travel by eliminating the overly soft and floppy conventional surround, thus keeping the driver’s motion more purely pistonic within its operational passband, for greater accuracy and lower distortion. The FST design is used in B&W’s speakers right up through their Diamond Series, which top out at over $20,000/pair!

The tweeter is an interesting driver. It utilizes a scaled-down version of B&W’s Nautilus tweeter rear enclosure, where the rear radiation of the tweeter is disseminated in a tapered chamber of non-parallel walls, thereby eliminating the possibility of the high frequencies being re-reflected through the dome and interfering with the tweeter’s direct radiation. As can be seen in the accompanying photo, the clear plastic tapered chamber is filled with damping material. There is no reason not to treat the high-frequency enclosure and radiator as an interdependent system, the same way the woofer and main enclosure are treated. Kudos to B&W for doing so.

 

B&W CM8 Tweeter

They could have done it even better in my opinion, however. Atlantic Technology in their $2500/pr AT-1 uses a 1 1/8” silk dome that is loaded into a bullet-shaped rear chamber. (See picture.) Since their enclosure also tapers into a non-perpendicular rear wall, there are no internal reflections that can come back up through the enclosure. However, the AT tweeter chamber is made out of drawn aluminum and functions as a very effective heatsink, since it physically contacts the tweeter’s back plate, forming a continuous thermal path with a massive surface area to pull heat out of the tweeter’s voice coil and magnet area. There is no reason that B&W couldn’t have done the same. As a matter of fact, there is no extra heatsinking on their tweeter at all and the rear chamber actually blocks some of the free air flow to the back of the small ceramic magnet and backplate, which is the part of the tweeter assembly that radiates the heat away from the driver. I’ll take on faith that B&W performed all the requisite power handling and life tests during development and that their tweeter is not prone to premature thermal failure. And in all fairness, the tweeter crossover is 4000 Hz, more than high enough to ensure that the tweeter doesn’t see any truly arduous current drive levels. Still at this price level, that rear chamber should have been aluminum, not clear plastic.

 

Atlantic Technology AT-1 tweeter

The crossover is a pretty conventional design, using standard parts. It is mounted on the inside of the bi-amp terminal assembly, which is part of the terminal cup/Flowport™ plastic molding. Two massive chokes are used and mounted at 90º to each other, to cancel out any magnetic interaction between the two. That’s smart design. They are also both strapped and hot glued down to the PCB, for a good mechanical connection and vibration prevention. The caps and resistors are regular-grade components, not audiophile-fringe grade. The Flowport has B&W’s trademark dimpling on the surface of the port tube, said to reduce port “chuffing.” The inside end of the port tube is also flared to reduce wind noise, which is where many manufacturers cut corners since it’s not visible from the outside of the cabinet. Again, this shows the careful attention to detail one expects in a premium-level product.

 

B&W CM8 Crossover

The grilles continued the theme of clever, thoughtful design. Imbedded into the grille’s frame were several small neodymium magnets. Just under the surface of the speaker’s front baffle—but not visible to the user—were either metal discs or corresponding neo magnets. When the grille was brought near the baffle, the neos “grabbed onto” their magnetic partners under the baffle’s surface, and the grille neatly and precisely snugged into place on its own. A firm but gentle tug was all that was required to remove the grille, and there was never any danger of the grille coming off on its own. No alignment by the user was necessary; once the magnets “grabbed,” the grille positioned itself exactly where it was supposed to, every time. Very, very nicely done, and the front baffle of the speaker was totally free of any visual obstructions like grille tree receptacles or grommets, etc.

 

B&W CM8 Grille Cover with Neo Magnets

My CM8 samples had what B&W called their Satin White finish. From the name “Satin White,” I was expecting a nice silvery-white finish, with a somewhat 3D depth and luster to it, similar to what premium automobile manufacturers use. Cadillac and Audi, in particular, offer a very beautiful white paint and I was looking forward to what B&W’s interpretation of this finish would be. Alas, I was a bit disappointed. The finish was a flat, plasticy white, akin to a white Formica countertop. While it wasn’t offensive per se, this was certainly the one area that my CM8’s came up short.

Set-Up

I set up and listened to the CM8’s in a 2-channel music system. The room was a small-to-medium sized 17 x 14 x 8 ft. These are very good sounding dimensions, since the length (17) is a prime number, and the height (8 ft) is not a whole number multiple of either the L or W. Therefore, these dimensions do not lend themselves to troublesome, additive bass/room resonances. The room has six 2 x 3 ft acoustic wall treatments staggered around the four walls (one centered on the front wall, two each at different heights on the side walls, and once centered on the rear wall between the two windows). There is a large sectional for seating and the floor is carpeted. Overall, the room is just slightly on the dead side of neutral, and it sounds excellent: solid, uniform bass, good imaging and detail, very little “ringing,” but live enough to let the speakers blossom out and fill the space with organic sound. Excellent recordings—especially of small-scale ensembles like jazz trio or solo piano—can sound almost live in this room. I have tremendous confidence that this room allows equipment to sound as good—or bad—as it can.

Associated Equipment

The rest of the system is simple but straightforward, and very high quality. The pre-amplifier/power amp combo was Parasound’s New Classic 2100 pre-amp and 2250 power amp, rated at 385 WPC 20-20k, into the 4Ω CM8’s. The CD player was the NAD 545 with Burr-Brown DACs. Considering the modest size of the listening room, this is more than enough clean, distortion-free power to ensure that the electronics never intruded upon the listening sessions in a negative way. Speaker wire was simple 14 ga. twisted-end, inserted into the holes in the binding posts. Basic Monster interconnects between the pre/power and the CD/pre. Nothing lunatic-fringe about the connectors and speaker wire, and more importantly, nothing that could even remotely be considered a defining or distracting influence on the sound.

The CM8s were set up according to B&W’s recommendations, about 2 feet from the wall behind them and about 2 ½-3 feet from the sidewalls. I experimented with placement by moving them closer to the wall behind them, but found that the balance got a little ‘tubby’ when the speakers were within about a foot of the wall. The speakers have very good horizontal dispersion and toe-in was minimal—perhaps 5-10º or so. Set up this way, the speakers threw a very solid, well-defined image with a good phantom center and relative immunity from stand-up/sit-down pickiness.

B&W; CM8 Floorstanding Loudspeaker Listening Tests

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 2^nd-order rolloff (12 dB/oct) to combine properly with the 2^nd-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

A 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

This 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

Wonderful 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.

B&W; CM8 Floorstanding Loudspeaker Conclusion

The B&W CM8s earned my ultimate respect for sounding quite excellent within their stated design claims. They don’t pretend to be truly full-range reproducers. Indeed, with bass rated to only 69 Hz, one might expect them to sound thin or lacking.

Such was not the case at all, however. Considered unto themselves, the CM8s were totally satisfying speakers. It was clean, honest and neutral at all times. I could detect a trace of midrange nasality from time to time, but it was ever-so-slight and never a distraction. Within its bass range, the reproduction was detailed, “fast,” and natural. The highs produced from the 1” aluminum dome with its Nautilus tapered chamber were consistently smooth and airy, without any sense of hotness.

The care taken in their design, manufacture, and choice of quality materials was evident at every point along the way where the user interacts with the product. This product has been thought through from start to finish and it’s both rare and pleasurable to experience that. As I mentioned previously, I’ve been intimately involved with the development and manufacture of consumer electronics for quite a long time, and I recognize the quality choices that B&W has made along the way in bring the CM8 to completion.

The CM8 a fine-sounding speaker system and a worthy addition to B&W’s reputation for excellence.

B&W CM8 Floorstanding Loudspeaker Review

MSRP: $1,100/ea

B&W Group North America
54 Concord Street
North Reading, Massachusetts 01864
Tel: +1 (978) 664 2870
Fax: +1 (978) 664 4109
Web: http://www.bowers-wilkins.com

 

About B&W

Named for founders John Bowers and Roy Wilkens, B&W is one the the world’s largest and most highly-acclaimed audio companies. From their first loudspeaker—the P1 of 1966—the company has consistently been at the very forefront of audio innovation with a long string of notable achievements such as the Matrix™ enclosure, their stunning Nautilus technology and their exclusive use in the renowned Abbey Road Studios as recording monitors.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Build Quality
Appearance
Treble Extension
Treble Smoothness
Midrange Accuracy
Bass Extension
Bass Accuracy
Dynamic Range
Performance
Value