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B&W DM 602 Series 3 Surround Speaker System

Thomas J. Norton, September, 2003

The model designation "DM" might not sound like anything special, but it has a long history with B&W. Models such as the DM 6, fondly remembered by audiophiles as the "pregnant penguin," enjoyed a modest following in the 1970s, when then-small English speaker company Bowers & Wilkins was knocking out attendees at hi-fi show demonstrations. B&W is now, by most accounts, the biggest speaker company in the UK. Its model range has increased exponentially since those early days, but the DM prefix is still very much alive.

The DM 600 line doesn't go back quite as far as the company itself—it only seems to. In this new Series 3 generation, the DM 600 remains one of the biggest bargains in audio—at least judging from the system that was the subject of this review.

Ins and Outs
The two-way DM 602 S3 is the heart of the system we requested for review. It's the largest bookshelf model in the model lineup, which includes the smaller DM 600 S3 and DM 601 S3, plus three floorstanders and two other models that can function either as center- or main-channel speakers.

B&W has added some significant refinements to all the new models, many of them filtered down from the development work done for the company's flagship Nautilus line. As in the Series 2, the tweeter incorporates a tubular loading chamber, similar to that used in the Nautilus, to minimize reflections on the back of the dome. But here a newly stiffened bond connecting the voice coil and dome extends the high-frequency range to a rated 30kHz (–6dB).

The DM 602 S3, with its 7-inch driver, is rated down to 43Hz (–6dB)—a range well suited to trouble-free blending with a good subwoofer. B&W has used woven Kevlar as a cone material in its woofer/midrange drivers since the 1970s, with continual subsequent refinements. The Kevlar drivers used in the new models include a more open basket structure than in the Series 2 designs, and, like the tweeter, have upgraded bonding between the voice coil and cone.

One obvious feature of the woofer/midrange driver is the bullet-shaped device visible at the center of the cone. Such devices, known as phase plugs, are typically used to smooth a speaker's response. In most applications, they are attached directly to the pole piece, part of the stationary magnet structure of the driver, and do not move. The phase plugs in the DM 602 S3 and LCR 600 S3 are attached to (and move with) the cone itself, so they also double as dustcaps.

Crossover refinements in the Series 3 include newly selected capacitors chosen after extensive listening tests. Readers new to audiophilia may scoff at the notion that different brands and types of components that have identical specs—and even test the same using conventional measurements—can have different audible effects on the sound. Not everyone agrees with this—it's as controversial as audible differences among cables. But many of us at the Guide have heard such differences for ourselves, and more than one specialist audio manufacturer evaluates equivalently rated parts from different sources as part of its product-design listening tests.

The enclosure of the DM 602 S3 is heavily braced. As in the last version, it uses B&W's FlowPort, a dimpled, tapered port outlet said to minimize turbulence and the noise that can result from it. B&W also provides foam plugs that can be inserted in the port to damp its output. This changes the speaker's bass characteristics and may be desirable in some installations. The only way you'll know which works better in your system is to experiment. I found that my setup worked best without the plugs; the bulk of the auditioning (and all of the measuring) was done with open ports.

All of the technology described above is also found in the LCR 600 S3, a speaker very much a part of the DM 600 series despite the lack of "DM" in its model number. (B&W probably felt that a model called the "DM LCR 600 Series 3" would fail the dealer tongue-twister test.) This speaker can be used horizontally as a center-channel, as I did, or positioned vertically and used for other channels as well. The LCR 600 S3 has two woofers, which are slightly smaller than the one in the 602, and a 21/2-way crossover. Both woofers operate up to 300Hz, but one driver rolls off above that frequency, leaving the other one to handle the 300Hz–4kHz range.

The LCR 600 S3's port is at the rear, and the speaker is magnetically shielded. The DM 602 S3 is not shielded—presumably because the left and right speakers will be at least a few feet from any television susceptible to magnetic fields. (CRT-based sets are susceptible; those based on plasma, LCD, LCoS, and DLP are not.)

Both the DM 602 S3 and the LCR 600 S3 have two sets of terminals and can be biwired or biamped, as desired. I used single wiring for all of my listening.

The ASW 675 subwoofer has been designed specifically for the new DM600 line, although, like all subwoofers, it can be used with other speakers. Its 10-inch driver has a long-throw suspension and a composite cone of Kevlar, pulp, and aluminum, driven by a 500W, class-D amplifier with a switching-mode power supply. Controls include level and crossover-frequency knobs, a switch to defeat the internal crossover for use with pre-pros and A/V receivers that have their own bass management (i.e., most of them), an 80Hz highpass filter that will most likely be used in 2-channel systems that lack bass management, a signal-sensing auto-on option, a 0/180 phase switch, and a two-position equalization control selectable for maximum output or maximum bass extension.

Cosmetically, the entire line has been completely redesigned. I think it looks great—particularly in the Sorrento "light oak" finish, a high-quality vinyl veneer—but judge for yourself.

Setup
I used two rooms and two different systems for this review. I broke in the review samples in my smaller room, approximately 17 feet long by 13 feet wide with an 8.5-foot ceiling. The DM 602 S3s were all mounted on stands situated at the left and right in both the front and rear. The front stands were the B&W designs shown in the photos. The center was perched atop my 50-inch Hitachi rear-projection TV in the small room, and the subwoofer was parked in the left front corner of the room.

All grilles were removed for the auditions, and no damping plugs were placed in the speakers' ports. The front left and right speakers were toed-in toward my listening position in both rooms. All of my listening was done with the subwoofer engaged and the bass crossovers in the receiver (small room) and pre-pro (large room) set to 80Hz. The "A" (maximum extension) position of the subwoofer's equalization switch produced the deepest bass response, though the difference between "A" and "B" (maximum output) was insignificant on most program material.

Article Continues:Page 2
B&W
Web Site

54 Concord Street
North Reading, MA 01864-2699
 
(978) 664-2870
>Page 1
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Specifications
Review System
Measurements

Sweet and Lowdown
I started listening in my smaller room. The first thing that struck me was the B&Ws' open, airy, well-balanced sound. The bass from the ASW 675 subwoofer was also punchy and solid, without boom. The imaging was reasonably precise, though the depth was a little foreshortened; both imaging and depth were likely more constrained by the presence of a large rear-projection television between the front speakers than by any inherent limitation of the B&Ws themselves.

The overall sound from the system was a bit laid-back, which made the treble a little prominent, but the speakers' top end was so clean, detailed, and sparklingly open that I couldn't work myself up into even a tepid reviewer's snit about it. And the B&Ws left no question that they could raise the roof on hyperactive soundtracks, even with moderate power in a medium-size room. Yes, there was a little congestion from the system at high levels on some complex material, but it was minor; otherwise, the 65Wpc Outlaw receiver drove the speakers without complaint.

The soundtrack from U-571 risked legal action (or at least a visit from the local SWAT team), and even at the highest levels I could stand, neither the main speakers nor the subwoofer complained—even during those hair-raising depth-charge attacks. Provided I did't drive the speakers to silly, head-banger levels—every speaker has its limit—they never sounded offensive or grating. The only reservation I had was a slightly woofy quality from the LCR 600 S3 center-channel on male voices, particularly off-axis. It wasn't difficult to adjust to—after a week or so I had to remind myself to listen for it—but it still kept the timbre of the front three speakers from being perfectly consistent.

The same open transparency I heard on soundtracks was also apparent on music. Driving only the left and right speakers plus the subwoofer in 2-channel stereo mode produced a natural yet robust and solid sound. Overall, the treble from the DM 602 S3 sounded a touch dry, and while high-frequency details were a little more obvious than I've heard from speakers that measure flat in the treble, the 602 never sounded edgy or bright. The subwoofer blended seamlessly, with no boom or other constant reminder that the system included a separate subwoofer. But when the music needed bass support, the ASW 675 punched through with a low end that was far tighter, more dynamic, and extended than any full-range speaker as small as the 602 can manage by itself.

The midrange on music also was consistently clear and uncolored, with perhaps just a touch of extra immediacy on vocals that wasn't unwelcome. This system—a pair of DM 602 S3s plus one ASW 675 sub—can easily compete on even terms with many comparably priced ($1600/pair), floorstanding 2-channel speakers. You might even find that you prefer it to some systems priced considerably higher.

Movin' On Up
The B&Ws were by no means at their best only in a small room; they were also at home in my main home-theater space: 26 feet long by 15.5 feet wide, with an 8-foot ceiling. In this system, the fronts and rears were again placed on stands. The center was mounted below my projection screen on a low stand made by B&W for their Nautilus series, and the subwoofer was placed in the right front corner.

With more power now on tap and more room for the speakers to unwind, I was even more impressed by what the B&Ws could do. Beginning with music playback—still 2-channel with subwoofer—Rickie Lee Jones' voice on "The Moon is Made of Gold," from Rob Wasserman's old audiophile standard, Duets (MCA MCAD-42131), sounded immediate and in the room, but not pushy. On other selections from this CD, the speakers excelled in soundstaging, detail, and transparency, with no congestion or obvious coloration. Only a bit too much sibilance on a few of the vocals suggested a little too much treble energy.

But soundstaging—both imaging and depth—was also clearly better in the larger space. (The projection screen was a couple of feet behind the plane of the speakers, making it less audibly obtrusive than the big-screen TV in the smaller room.) From the delicate fingering of acoustic guitar to the deepest bass, the only things I found to criticize about the 2-channel sound of the B&Ws were the tendency toward a crisp top end and a little lack of warmth and weight in the "power" region, the range in the audible spectrum centered around 300–400Hz. Symphonic music, while loaded with detail and a realistic sense of space, was a bit shy of the majestic quality that larger speakers—usually far more expensive ones—can produce.

Moving on to movies, the soundtrack from the newly remastered Patriot Games was a bit too bright in Dolby Digital, but noticeably better in DTS. Otherwise, the balance was first-rate, with a superb rendering of the light and airy panpipes and tight, explosive drums of composer James Horner's exciting score.

And Fools Rush In—not an overly challenging soundtrack, but one of the cleanest and sweetest in my DVD collection—sounded as good as it does through speakers costing several times as much as the B&Ws. This soundtrack is loaded with detail, but the top end is not exaggerated. Still, on some DVDs—and bright ones aren't hard to find—the B&Ws continued to sound just a little too crisp. The obvious solution was some sort of cinema equalization in the receiver or pre-pro. But I liked the sparkle the B&Ws provided on many soundtracks, and the selectable cinema EQ on the Outlaw pre-pro I used for much of my listening was a bit too aggressive, reducing the transparency too much for my taste. Changing over to the much more expensive Primare SP31.7 pre-pro and A30.5 power amp helped noticeably. The overall balance remained the same, but now the top end was more refined.

On the last night of my listening tests, I went on an animation binge. The Chubb-Chubbs sounded slightly laid-back, delicate in the high end and solid in the bass, without unnatural emphasis. Scrat's Missing Adventure, a short subject included on the Ice Age DVD, was well-balanced overall, with a bottom end strong enough to shake my large room nicely. And the opening sequence of Titan A.E. was as dynamic and explosive as you'd expect the violent destruction of the Earth to be, its bottom end almost alarming enough to set off an earthquake alert here in Southern California. But the good stuff was not limited to explosions and seismic disasters. The music on the superbly recorded Fantasia 2000 sounded spectacularly good, with a spread, depth, and envelopment that were astonishing for a surround speaker package that might well be considered B&W's entry-level, bread-and-butter line by serious enthusiasts.

Apart from the slightly prominent top end, the only other reservation I had about the sound of the DM 602 S3 system was a little heaviness in the lower midrange, obvious primarily on male dialogue and singing voices. It clearly originated from the LCR 600 S3 center-channel and was evident in both the smaller and larger systems. This probably won't be a factor in all installations, depending on the speaker placement, but in any case it wasn't entirely a negative in my situation on soundtracks. It did add a little welcome warmth to the overall sonic palette. I had a spare DM 602 S3 on hand (B&W sent along an extra pair), and when I substituted it as a center-channel speaker, that extra warmth disappeared. And while the sound from a center 602 was a little more consistent off-axis and slightly more balanced on vocals than the LCR 600 S3, the system overall was now just a little lean with full surround material.

If you decide to go that route and use DM 602 S3s all around, remember that, unlike the LCR 600 S3, the 602 is not magnetically shielded. Nor should it be placed on its side for center-channel use. And you might have a problem buying an odd number; the 602s are packaged as pairs. (The extra one could be used for a center surround in a 6.1 system!)

Conclusions
At $2700, this B&W system, built around the DM 602 Series 3 speakers, is not cheap, but compared to what you can pay these days for a complete home-theater speaker setup, it's still a bargain. It's a surround package that anyone can appreciate; even in 2-channel mode, it can compete with many stereo speakers that cost $2700/pair—except that here you get the bonus of a full 5.1-channel array. It will work well with modestly priced receivers or separates, but it won't embarrass far more expensive pre-pros and amps. These B&Ws are special, and highly recommended.

Article Continues:Specifications
B&W
Web Site

54 Concord Street
North Reading, MA 01864-2699
 
(978) 664-2870
Page 1
>Page 2
Specifications
Review System
Measurements

Specifications

DM 602 S3 2-driver, 2-way ported-box speaker
Drivers: 1" alloy-dome tweeter,
7" woven-Kevlar bass/midrange cone
Frequency response: 52Hz–20kHz, +/-3dB on reference axis
Frequency range: –6dB @ 43Hz & 30kHz
Harmonic distortion: 1%, 2nd and 3rd harmonics (90dB/m), 60Hz–20kHz
Nominal impedance: 8 ohms (minimum 4ohms)
Crossover frequency: 4kHz
Recommended amplifier power: 25–120W into 8ohms
Sensitivity: 90dB/2.83V/m
Dimensions: 19.3" x 9.3" x 11.5" (HxWxD)
Weight: 23.1 lbs
Price: $600/pair

LCR 600 S3 3-driver, 21/2-way, ported-box, magnetically shielded speaker
Drivers: 1" alloy-dome tweeter, two 6.5" woven-Kevlar bass/midrange cones
Frequency response: 58Hz–20kHz, +/-3dB on reference axis
Frequency range: –6dB @ 48Hz & 30kHz
Harmonic distortion: 1%, 2nd and 3rd harmonics (90dB/m), 70Hz–20kHz
Nominal impedance: 8 ohms (minimum 3ohms)
Crossover frequencies: 300Hz, 4kHz
Recommended amplifier power: 25–150W into 8ohms
Sensitivity: 89dB/2.83V/m
Dimensions: 21.5" x 8" x 12.2" (WxHxD)
Weight: 27.5 lbs
Price: $500 each

ASW 675 sealed-box, powered subwoofer
Driver: 10" long-throw, aluminum/paper/Kevlar cone
System frequency response: 22–110Hz (adjustable, 31–110Hz), +/-3dB
System frequency range: –6dB @ 17 & 140Hz (adjustable)
Amplifier: 500W continuous, 33k ohms input impedance
Dimensions: 13.4" x 13.4" x 16.2" (HxWxD), excluding feet, including rear-panel controls
Weight: 56.1 lbs
Price: $1000 each

System
Finishes: black ash, light oak vinyl
Price: $2700 as reviewed; add $45 each for B&W 20" stands

Manufacturer
B&W Loudspeakers of America
54 Concord Street
North Reading, MA 01864-2699
tel. (978) 664-2870
Fax (978) 664-4109
www.bwspeakers.com

Article Continues:Review System
B&W
Web Site

54 Concord Street
North Reading, MA 01864-2699
 
(978) 664-2870
Page 1
Page 2
>Specifications
Review System
Measurements

Review System

Sources
Integra DPS-8.3 DVD player
Panasonic DVD-RP56 DVD player
Receiver & Preamp-Processors
Outlaw 1050 receiver
Outlaw 950 preamp-processor
Primare SP31.1 preamp-processor
Power Amps
Outlaw 750
Primare A30.5
Cables
Digital: Kimber Kable AGDL
Interconnect: Madrigal CZ-Gel, Monster M-1500
Speaker: Monster Cable M2.2, Monster THX, XLO VDO

Article Continues:Measurements
B&W
Web Site

54 Concord Street
North Reading, MA 01864-2699
 
(978) 664-2870
Page 1
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Specifications
>Review System
Measurements

Measurements

The B&W DM 602 S3's bass alignment is tuned to approximately 38Hz (the minimum impedance magnitude in the "saddle" between the two main impedance peaks typical of a ported enclosure), with a minimum impedance of 2.91ohms at 12.5kHz. This high-frequency minimum will not unduly stress an amplifier, particularly since the phase angle of the impedance at this frequency is a benign –10. The next lowest value is 4.73ohms at 172Hz. The 602 should be an easy load to drive for any competent amplifier. The speaker's sensitivity measured approximately 87dB/W/m across most of the midrange and treble—somewhat lower than specified, but an average value for a contemporary speaker.

All frequency-response measurements were made with no plugs in the ports. The horizontal front response of the DM 602 S3 is shown in Fig.1 (violet), the pseudo-anechoic response averaged over a 30 forward horizontal angle, at tweeter height, and combined with the nearfield responses of the woofer and port. The 602's effective lower limit (–10dB at 33Hz) is very good for a speaker of this size, though it begins rolling off gradually just below 100Hz.

Fig.1: B&W DM 602 S3, pseudo-anechoic response off horizontal axis at 45 (red) and 60 (blue)

The overall 30 front horizontal response of the 602 is smooth from about 200Hz to 7kHz. The main aberration is an obvious rise centered at 9kHz. This peak is nearly the same on-axis and 15 off-axis, but it smooths out dramatically at 30 off-axis and is consistent with the high-frequency response I heard in the listening tests. The high frequencies roll off smoothly at extreme off-axis angles, though a dip starts to appear at around 2–3kHz, reflecting the decreased dispersion of the woofer, which is still active at those frequencies.

All measurements presented here were made with the grilles removed. The response of the 602 was also measured on-axis with the grilles in place, in which case it was noticeably more erratic through the upper midrange and low treble, but with no significant effect on the 9kHz peak.

The vertical response shown in Fig.2 indicates that the DM 602 S3 should sound best when the height of the listener's ears is as close as possible to that of the tweeter. Standing up puts a pronounced dip in the presence region—something to keep in mind when auditioning these speakers.

Fig.2: B&W DM 602 S3, pseudo-anechoic response at 15 above (red) and 15 below (blue) tweeter.

The LCR 600 S3 center-channel speaker is tuned to about 33Hz. Its impedance reaches a minimum of 3.1ohms at 14.5kHz, but, as noted above, this is less significant than the 5.1ohms minimum at 33Hz. In any case, the speaker should be a relatively easy load to drive. Its sensitivity measured approximately 87dB/W/m.

The LCR 600 S3's measured front horizontal response, taken on the tweeter axis and averaged in the same manner as described above for the DM 602 S3, is shown in Fig.3a and Fig.3b. The speaker's effective lower limit (–10dB) is approximately 45Hz. Because of the 21/2-way design of the crossover, the 600's horizontal dispersion is asymmetrical; that is, different in different directions. Such a 21/2-way network may have useful characteristics, but improving the horizontal dispersion of a horizontally configured center-channel is not one of them, as we have seen in other, similar designs. While it isn't shown here, even sitting 15 off-axis on the side nearest the port results in a dip of about 5dB centered at about 4kHz. This explains the slight woofy quality noted in the sound, particularly on vocals.

Fig.3a: B&W LCR 600 S3, pseudo-anechoic response off horizontal axis at 45 (red) and 60 (blue) in direction of port.

Fig.3b: B&W LCR 600 S3, pseudo-anechoic response off horizontal axis at 45 (red) and 60 (blue) in direction away from port.

The 600 S3's vertical off-axis response is very smooth (Fig.4). In fact, it is actually a little flatter at +/-15 than it is on-axis, suggesting that the speaker might sound best when not aimed directly at the listener in the vertical plane. For example, when placing the 600 atop a big-screen TV, aim it straight ahead rather than angled down.

Fig.4: B&W LCR 600 S3, pseudo-anechoic response at 15 above (red) and 15 below (blue) tweeter.

The measurements of the DM 602 S3 and LCR 600 S3 are good for speakers in this price range. The only two results that gave me pause were the 602's peak at 9kHz and the 600's horizontal off-axis response deviations. Neither problem area was as obvious on normal program material as the measurements might suggest, though the high-frequency rise in the 602 did make the speaker more critical of brightness in the program material and/or associated components. The 600's horizontal off-axis dispersion is typical of nearly every 2- or 21/2-way center-channel we have tested in which the drivers are oriented horizontally. The best way to optimize such a speaker is with a 3-way design in which the midrange and tweeter are mounted one above the other, flanked by woofers on each side. B&W uses this approach in its more upscale models, but it isn't cheap to do well.—TJN

B&W
Web Site

54 Concord Street
North Reading, MA 01864-2699
 
(978) 664-2870
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