B&W DM305.

Manufacturer: B&W Loudspeakers of America, 54 Concord St., North Reading MA 08164-2699; 508/664-2870

Price: $450/pair

Source: Manufacturer loan

Reviewer: Howard Ferstler

The British speaker company B&W has earned a well-deserved reputation as a producer of top-grade, audiophile loudspeakers for the discriminating enthusiast. However, their reputation has mostly been made because of what they have produced in the way of upscale models, a few of which are considered "reference standards" by many enthusiasts, including some audio journalists.

The company has recently come out with some new, lower-cost designs. One likely purpose of this maneuver is to satisfy discriminating buffs on a budget. However, if this new line is successful, it will probably help to introduce B&W products into the lucrative mainstream American market. The more budget-oriented customers the company attracts (assuming they are happy with their purchases), the more upscale speakers they will eventually sell to those who purchased start-up systems from them and want to trade up. One of these was the DM-302, reviewed in Issue 63. Another is the floor-standing DM-305, the system that we will be dealing with here.

Specifications and Descriptions: The DM-305 is an attractively finished, 8-ohm-rated, two-way system, fitted out with a 1" dome tweeter and 6.5" woofer/midrange (the latter being larger than the one in the DM-302). These are located, tweeter-above-woofer, in the upper half of a moderately sized "tower" enclosure utilizing a 4th-order, vented-box design. The cabinet is about 33" high, 8.5" wide, and about 12" deep, and the total package weighs in at an easy-to-maneuver 24 pounds. The sides and top of the enclosure are finished in simulated wood-grain, black vinyl (the only color available). However, besides the vinyl surface, the enclosure is embellished with a few other interesting substances.

Most of the structure is standard particle-board under the vinyl surface, but the front has a cosmetically attractive plastic panel covering the entire area (the drivers are bedded in nicely at the top, with a cloth-cover grille snapping into position to protect them), and the upper half of the back is made up of what at first resembles a deeply sculpted, plastic grid-like pattern. However, a closer look reveals that the heavy plastic latticework is actually the backside of a molded array of alternating horizontally and vertically arranged wedge shapes. On the inside of the box, these extend forward toward the woofer, miniature anechoic-chamber-like. The wedges help to break up internal standing waves, at least in the upper bass, and apparently have advantages over simple fiberglass stuffing, which will not deal with those frequencies as well as the wedges. The company calls this array a "Prism System" (patent pending).

The DM-305 comes with the requisite, screw-in spiked feet (the company suggests that you install them after you have determined where you want the speakers to be positioned), and has connections on the back that will accept standard wire, spade connectors, or pin hookups. The connectors have little caps in their ends and if those caps are removed, the speakers will also accept single, but not double, banana plugs. (You can pop out the plugs with a bit of careful assistance from a common screwdriver). The owner's manual made no mention of the caps or the banana-plug option.

There are two pairs of these speaker connectors, which means you can biamp or biwire if you choose. (Both of these practices would almost certainly be a waste of time with speakers in this price category, and I have to interject here that I believe that biwiring is a waste of time with any system, unless all you have on hand is really skinny wire). The connectors are jumpered together by plated copper strips that must be carefully positioned for a proper connection. If you use a bare-wire or pin hookup, you will have to be very careful to make sure the jumper strips make good contact. During my testing procedures I occasionally had a tweeter or woofer disconnect, even though the lock nuts were tightened adequately. I suppose this makes a case for banana connectors pushed into the jacks revealed by removing the plastic plugs -- or even bi-wiring, even though a good single wire hookup should sound as good as the latter.

Each speaker is rated for use with amplifiers of from 25 to 120 watts per channel. Going above 120 would certainly be overkill, and going below (say, with some kind of ultra-expensive, single-ended, tube-equipped contraption), would be nonsense. (It would be nonsense with any other speakers, also).

The woofer driver has a more elongated dust dome than one usually sees, possibly to help disperse the midrange. However, it probably also functions as a damping weight. Besides the wedges and the dome, the woofer system has another interesting characteristic, in that it includes two ports of different size and in different locations. One, a rectangular slot, is on the front, right under the woofer. The other, a typical round port, is located on the back.

According to a spokesman at B&W, the dual-port arrangement was designed by the engineers at their Steyning, England research facility to gain greater sensitivity and to extend the low-bass frequency response. This is a notable goal, and if two very different ports are required for the job, more power to B&W for using them. The system's rated sensitivity is a somewhat higher than average 91 dB (2.83 volts input, measured at one meter). The improved sensitivity is probably one measurable offshoot of the port design.

The owner's manual is written in 8(!) languages, a record in my book, and consists of one page of instructions in each, plus a diagram on the inside of the back cover. The manual is decently comprehensive, and while not exactly a dissertation on speaker theory and use, it should satisfy all but the most information-crazed enthusiast. The section on "positioning" recommends placing the speakers so that they are sited at the corners of an equilateral triangle, a good practice for the best in soundstage width and depth. For the best soundstage imaging, the manual also recommends toeing the speakers inward, a practice I agree with in this case (see below).

Measurements and Impressions: Using my AudioControl SA-3051 1/3-octave RTA, I took a number of measurements around my main listening room at a variety of speaker and listener locations. I also set up one of the 305s on my back deck and did some measurements out there to better determine characteristics in a semi-anechoic, almost reflection-free environment. (Under normal conditions, the outdoors is only partially anechoic, unless you suspend the speaker up fairly high, because the ground is still close enough to reflect; only skydivers experience true anechoic conditions at all audible frequencies).

Outdoors, I discovered that the close-up, on-axis response of the system was exemplary. However, we do not listen that close and normally do not listen outdoors. Off axis, the response was less smooth, particularly well off to the sides and up near the 3 kHz crossover point, and the overall level was considerably subdued compared to the on-axis readings. This off-axis attenuation will be seen as an advantage by some and as a disadvantage by others.

Indoors, I found that the most representative microphone position was along the horizontal axis of my preferred listening couch, and that I could get a good, smooth room-response measurement by moving the capsule over a three-dimensional area that would be occupied by anyone sitting anywhere along its 7-foot length. I used a 20-second averaging function (which the SA-3051 can do automatically) and plotted several curves to ensure consistency. For added accuracy, I combined some of those curves into a still longer average. A measurement technique like this, although not as comprehensive, as would be possible with a gated system that could deliver reflection-free measurements at assorted angles (at least at midrange and higher frequencies), gives one a passably decent idea of the room-response characteristics of a speaker system, or systems.

While this will not tell us much about the direct-field performance that may be of importance to individuals who crave precise soundstaging and imaging and prefer to sit centered up and close to toed-in speaker systems so as to best experience those artifacts, it does do a decent job of determining the power output of a system into a typical listening area. Thus, in some ways it more clearly defines how a system might perform in terms of frequency balance for those who listen in the more commonly experienced reverberant field.

Overall, the DM-305 exhibited decent room-response flatness over a 150 Hz to 12.5 kHz range, with the flattest performance happening when it was pulled out from the front wall about a foot. Deviations were in the neighborhood of [+ or -] 4 dB, with the largest aberrations including a dip centered at about 2.5-3 kHz and a somewhat milder dip centered in the 300 Hz area. The treble extension was very good, with the average only 4 dB down at 16 kHz.

The upper-frequency dip is probably a crossover artifact resulting from the narrowing response of the woofer/mid suddenly flaring outward as the frequency climbs and the higher frequencies begin to dovetail into the bottom of the tweeter range. This is a common artifact with two-way speaker systems having rather high crossover points, because they are stuck with low-range drivers that must also perform as rather large-diameter midrange drivers. As it nears the crossover point, the woofer/midrange driver becomes less efficient at putting flat power into the room, and when the response climbs high enough to engage the tweeter, the off-axis response (and therefore the average power response) comes back up. The result is a dip leading up to and including frequencies adjacent to the crossover point. A power-response dip like this can be difficult to shake, particularly if the designer also wants smooth on-axis response.

The lower dip is probably a boundary artifact, resulting from the high placement of the woofer/midrange driver. Indeed, when positioning this system out from the front wall, the flattest midbass performance will result if it is located so that the distance from a point directly in front of the center of the woofer/mid's cone to the floor is substantially different from its distance to the front wall and/or the side wall. Doing this will reduce mid-bass, quarter-wave cancellation artifacts (suckout) that will always put dips into the frequency-response of two-way speaker systems with high-mounted woofers. I should note that this includes small boxes placed on stands.

Although midbass cancellations are much easier to control with three-way systems, this will only be the case if their woofer drivers are close to the floor and the woofer-to-midrange crossover point is adjusted to take advantage of that placement. It is impossible to eliminate them with two-way models, but their effect can be mitigated by intelligent positioning of the enclosure.

The bass response of the 305s was decent, when one considers the size of the woofer and the 91 dB sensitivity rating. Response was reasonably good down to about 100 Hz, where the response gradually began to rise and reached a peak several dB above midrange level at about 50 Hz. (Tuning a system for a peak like this is commonly done and a good way to get a small-woofered package to deliver decent bass over the range covered by most recordings). Below that point, the response rolled off precipitously, with the sound more and more dominated by harmonics.

At very low frequencies, the bass/mid driver was decidedly out of its league, and was calling for assistance from an outboard subwoofer. For example, with a 20-Hz test tone fed in at a moderate level, my RTA indicated a higher output at its 63-Hz test point (indicating a third harmonic at 60 Hz) than at 20 Hz, and by a substantial margin. Subjectively, the resulting sound was nothing like a 20-Hz signal. As a point of reference, the same tone fed into one of my Allison LC-120 two-way models (these have 8" acoustic-suspension woofers) resulted in a clean, but subdued 20-Hz sound, with no blatantly audible harmonics.

I did a number of other comparisons between these two systems, using both music and test signals (and a nifty little switchbox I cobbled together one weekend), because the LC has been highly regarded for some time. (It, like a number of other Allison Acoustics models, had been highly rated by Consumer's Union, who make power response the focus of their testing procedures). The LC-120 displays flat power response at all midrange and treble frequencies, and as a result of its design goals, it exhibits very wide dispersion from 2 kHz on up. The result is a somewhat diffuse and spacious sound, rather than pinpoint imaging and focus. While it may not be everyone's cup of two-way-speaker tea, it is a system that I am used to, making it a decent point of reference when auditioning other speakers in this price class.

For most of the comparisons, the speakers were placed equal distances apart (one pair staggered slightly to the right of center and the other staggered slightly to the left), with their front panels about 30 inches out from the front wall and with about 9 feet of space between the left and right units. To get their tweeters at nearly the same heights, I put the physically shorter 120s on 1-foot-high stands, compromising their midbass flatness somewhat. Because I was mainly interested in comparing imaging and spaciousness, this did not matter to any great extent, and it did not impact deep-bass performance.

While music-reproducing ability would have to be the most important thing in any comparison of speakers, some of the test-tone sequences I used were still very revealing. As noted, with a 20-Hz tone the DM-305 exhibited pronounced third harmonic distortion. The LC did not. When comparing the total outputs of each at that frequency with a basic SPL meter, they were both about the same -- fairly low -- in comparison to the midrange level. However, while the LC's output was mostly at 20 Hz, the sound produced by the 305 was dominated by odd-order harmonics, at an equally subdued level. Both systems sounded equally loud down really low, but the LC produced real bass and the 305 produced distinctly audible distortion. Again, this was with test tones, not music.

I got similar results at 30 Hz, and you could even hear a difference at 50 Hz, although by then it was slight as long as the levels were not elevated too high. Of course, I suppose it is unfair to compare an 8" woofer to a 6.5-incher, but the 305 has a list price of $450 a pair, while the LC cost $340 a pair before it was discontinued a few years back. (The LC-120's replacement, the AL-115, cost about the same as the DM-305 when it was discontinued a couple of years ago, and was electro-mechanically the same as the LC-120). Anyway, I believe it is fairer to compare systems based on their cost, rather than their driver sizes.

In any case, we should not sell the DM-305s' woofer/mid drivers short. They pretty much behave as any decent drivers in that size category do in terms of deep bass. The dual-port and prism design, while possibly slightly helpful as ported designs usually are in terms of allowing the system to generate reasonably high sound levels down fairly low, does not perform in any particularly special way at normal listening levels. If you have a decent subwoofer (and with this system I suggest you employ one if you enjoy organ music or intend to use the systems with dynamite-grade home-theater program material), the differences in deep bass become academic, and the DM-305s' strong points will be allowed to better display themselves. (Note: during one listening session, I coupled the DMs with the Hsu Research TN1220HO sub in my second system, and the results were sensational).

Those strong points involve the kind of imaging, focus, and soundstaging that many audio enthusiasts consider essential to good high-fidelity sound reproduction. With pink noise left-to-right sweeps, courtesy of the Delos Surround Spectacular disc (3179), the B&W was more able to present a tightly focused image than any of my systems -- including even my big Allison IC-20s, which are manifestly larger and more sophisticated than the LC-120s. With the 305s, the L-R sweeps were stable and well focused all the way across the soundstage between the speakers. With the LC-120s, the image was reasonably tight at the left and right extremes, but as the sweep moved across the stage it would spread out slightly and extend toward the opposite speaker.

Interestingly, with center-stabilized, pink-noise inputs, the tighter focus of the DM-305s in comparison to any of the Allison models was still evident. In addition, when switching from one system to the other, the centered random noise produced by the 305s was subjectively closer sounding, even though the relative levels were quite similar.

This ability to tightly focus a center image has been important to audio enthusiasts ever since two-channel stereo appeared. However, I have to point out that as more and more systems begin to employ a center channel (and this will be very important as we begin to see more and more audio as well as video recordings done in 5 and 5.1 channel surround), the ability to form a tight, well-focused image with only two speakers up front will be less critical. A phantom-center channel is an unnatural thing, and while it is terrific when a pair of speakers can give us one that is sharply delineated, the ability to do so will become less critical as time goes on.

When moving off the listening axis, the B&Ws displayed somewhat more image shifting toward the nearer speaker than did any of the somewhat more diffuse-sounding Allison models, unless the DM-305s were toed in considerably. If done right, this placement technique engages a kind of time/intensity trade off (and further reduces sidewall reflections, for an even tighter degree of focus in the center), and I recommend it highly when listening to these or any other speakers designed for a flat first-arrival signal, precise imaging, and which display an off-axis response that is possibly both somewhat irregular and attenuated.

With most musical material containing substantial bass, artifacts discovered when utilizing bass test tones will nearly always be less apparent, mainly because most recordings have enough mid and upper-bass harmonics of their own to partially mask speaker-system distortion and low-bass limitations. However, when doing my comparisons, recordings with really potent bass pedals did highlight the advantages a good 8" woofer has over a smaller one. With a Mendelssohn Organ Works recording that I use to regularly test system bass response (Argo 414 420), the Allison LC-120s delivered very subdued, but still relatively clean, sub-20-Hz pedal notes, while the DM-305 just emitted fluttering sounds. With Mary Preston Playing the Myerson Symphony Center Organ (Gothic 49079), the flutter effect was decently masked by the harmonics of the organ itself, but the lack of pedal-reproducing ability was still apparent. However, with virtually all pop material that I tried (for example, Donald Fagen's The Nightfly (Warner 23696), some of the pop tracks on the Hi-Fi News and Record Review Test Disc II, and even Dire Straits' On Every Street (Warner 22680), which has fairly potent bass at times), the B&Ws did quite well in the bass department.

The imaging contrasts were just as notable with musical material as with the pink-noise tests. For example, with a really well-imaged recording such as Colors of the Baroque (Summit DCD 108) and the Durufle Requiem (Summit DCD 134) the ability of a pair of DM-305s to present a well-defined soundstage were clearly evident. The ensemble was positioned between the speakers and the assorted performers were quite easy to pinpoint, provided the one listened from the preferred sweet spot. The Allison LC-120 speakers, in contrast, displayed a less focused soundstage, but their wider dispersion at higher frequencies made that soundstage subjectively a bit more wider and the front-to-back depth also seemed better.

This contrast was most apparent when listening from well back into the reverberant sound field. From up close, and with the speakers toed in toward the listener, the B&Ws had a decided edge in the clarity department, almost certainly due to the more coherent, flatter on-axis performance. The LC-120s, by way of contrast, were not as solid sounding and had a more diffuse soundfield.

When listening to a solo vocalist (in this case, Mozart Arias, with Cecilia Bartoli: London 430 513), the British speakers delivered a tighter central image, while the Allison models were more diffuse, presenting a more spacious environment around the singer. With the DM-305s, the soloist was pulled forward more in relation to the supporting ensemble, something that listeners who are interested in front-row-seat vocal articulation will be pleased with. With the LC-120s, the soloist, although not as well defined, was also more distant-sounding. Located in a decent room, and properly aimed at a listener occupying the sweet spot, a pair of 305s has the ability to delineate a properly recorded centered performer the way a camera lens does in the visual realm -- when carefully adjusted to "snap" the image into focus.

All of my listening tended to substantiate my views that the DM-305s are clearly in the B&W tradition of providing terrific soundstage imaging and very good focus, particularly if the listener sits closer to them than about 10 feet and toes them in so that they are either aimed at the sweet spot or even angled inward a bit further. Doing this helps to provide the above-noted time/intensity tradeoff needed to broaden the soundstage to include listeners other than those in the best-seat listening position in the center. Further away and more into the reverberant listening field, the tight imaging continues to hold and sets these speakers apart from very wide dispersion models like the Allisons, which tend to offer a more diffuse but broader soundstage.

If you like your imaging tight and you are on a limited speaker budget, there is little doubt that you will not be disappointed by the DM-305s. If you require deeper bass than they offer, the addition of a powered subwoofer with a built-in crossover of decent quality will not only give it to you (B&W has what appear to be some exciting new subwoofer models that should be compatible with the 305s), but will also free up the small woofer to do what it does best: deliver a clean, focused midrange.

-- HF