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B&W DM110/DM220

Speakers


These speakers from B&W are low cost spinoffs from their 801 model, which is used for the monitoring of classical music by several recording companies both here and abroad. They come with a 'digital' label, yet feature a low sensitivity (for Rock) of 90dB/1W/1 metre.


DM220



Beginning with the larger model there are three drive units: one 8" driver is Thiele-loaded, and covers the low bass (below 120Hz). Higher frequencies are passed over to a second 8", which handles the high bass/midrange, then at 3kHz up to the tweeter. The crossovers involved here are different from most: the low bass unit is fed via a -6dB/octave filter, whilst the high bass/mid driver is rolled off at -24dB/octave. This is difficult to achieve electrically using only passive components, so B&W have carefully juxtaposed a -12dB/octave electrical roll-off with the driver's own (natural) -12dB/octave acoustic roll-off, to give a fourth-order (24dB) slope overall.

The potential advantage of using two 8" drive units to cover the lower regions is to double up on acoustic power; you have twice the cone area working on the air, to bring up low bass levels below the frequency where they'd otherwise begin to roll-off. Power handling capacity in the low bass is likewise enhanced. At frequencies above this region, the lower driver gracefully bows out (at a rate of -6dB (=half-power) for every octave), leaving the single (upper) 8" to cover the critical midrange region.

If this wasn't done, the lower driver would affect the radiation pattern, and problems in the realms of phase, imaging, frequency response and direct vs. reverberant field relationships would rear their head. In short, a mess... True, two 8" drivers working together in the midrange would double up PHC (power handling), but this is the region where extra PHC is needed least of all.

The manufacturer's reason for offering extra power handling in the low bass relates to Compact Disc use in the home, wherein many hi-fi speakers will be receiving more low bass energy than they've been accustomed to in the past, vis-a-vis vinyl discs. But, for studio purposes, we're already dealing with the 'original' sound - raw bass and all. So the LF (Low Frequency) performance of these speakers is important regardless of any 'digital' label.

Assembly



At first sight, the cabinet appears to be a one piece plastic moulding. This is basically the case as regards the exterior, but looking inside, the main body of the cabinet is the usual high density chipboard.

The DM220's grille should be removed for best results, but sadly, the mid/bass drivers sport brash red plastic rings around their edges, which clash noisily with the otherwise subdued tones of brown. This is usually the case when a manufacturer pays for 'styling' - and then boasts about it in the literature.

Inside, the crossover components are glued on the terminal plate and are connected to their respective terminals by solder tags clamped under the terminal nuts. The threads here aren't sealed or locked in any way; this error is serious, as any amount of use will cause one of both nuts to loosen, leading to intermittent sound, severe distortion, disconnection of parts of the crossover and even damage to the drivers. Indeed, during initial tests, it was necessary to tighten these connections to overcome the problems just described. Before purchase then, you should ask you dealer to (1) check the tightness of the said connections, and (2) see that the threads are locked.

Moving round to the outside, the terminals don't grip either banana or bunch-pin plugs adequately, and are spaced too close together for easy wire clamping. Much better 4mm binding posts are available, and B&W should use them if they wish to develop credibility in the professional field.

DM110



From a design viewpoint, this unit is unexceptional, embodying techniques we've looked at in previous reviews. It's a two-way system, with a single 8" bass/mid driver, Thiele loaded. Only the crossover is different from most; it's a -24dB/octave type, again, part acoustic and part electrical. The cabinet is substantially identical to its larger brother, and... oh dear... the same execrable terminals.


Listening Tests



The DM220s were recessed - they lack the essential slight 'bite' in the high midrange that comes with a dead flat or slightly proud response. Instead, B&W appear to have opted for leaving a suckout up to 6dB deep around 4 to 6kHz, presumably because many people find this preferable. This will result in difficulties on snare sounds and some vocals. The suckout also makes the high treble 'tizz' unduly prominent. The bass is solid, slightly boxy and there's a distinct muddiness in the low mid. This is only to be expected, for both 8" drivers are working together in this region. As for depth, the DM220 has a hint of the sort of bottom end a top Thiele design (like an EV TL606) achieves, which is to be expected, for two 8" drivers have a greater piston (air moving) area than a 15" driver.

The real problem with any speaker of 90dB sensitivity coupled with a relatively low power handling capacity is that it runs out of steam before any truly low bass becomes audible; high SPLs are necessary before our ears even begin to register the lower fundamentals on kick drums and bass. There is also some overhang in the bass - percussive sounds do not stop as sharply as they might.

The DM220 is rated at 100 watts maximum, but just to prove this rating, we tested the speakers on the Yamaha PC2002 amplifier (reviewed in February HSR) which offers up to 250 watts into 8 ohms. As you'd expect, there was considerable distortion and compression as the speaker was taken up to 250 watts, but no damage - and a much improved low bass sound to boot. This proves the point that large amplifiers are quite safe and indeed, advantageous provided they're driven with care. In this instance, the PC2002 offered a very welcome additional 4dB of headroom for peaks, and an amplifier of this capacity would make the most of the DM220.

The imaging is stable, but nothing special, whereas the listening position for best stereo wasn't at all critical. On a more positive note, the soundfield proved to be exceptionally uniform around the room. The DM220s come with a sensibly written leaflet discussing speaker positioning and the role of phasing and connecting leads.

The DM110 is considerably different to the 220: the sound is pleasantly forward in the high-mid, by 2 or 3dB over the DM220 in the 2.5kHz to 6kHz area. This brings the high treble into correct perspective, and instils the all-essential 'bite'. In addition, the 110s don't exhibit the low midrange muddiness, and the imaging is far superior - as is to be expected with fewer drive units and a fourth order crossover. Indeed, it has perceptible 3D qualities like the Kord Tornadoes.

The trade-offs you'll have to suffer are (i) a marginally reduced power handling capacity, and (ii), less low bass energy, neither of which are particularly significant in practice. Indeed, the DM110s were run up to 250 watts on the PC2002 amplifier with no ill effect (despite the official 75 watt rating), though you should listen carefully for any popping noises as the cones bottom, and back off the gain until this ceases. The maximum drive level will in most cases be governed solely by the level of low bass energy in the music.

Conclusions



The DM110 is an excellent all-round performer. It embodies much of the finesse of more exotic speakers, and is almost a giveaway at the asking price. At the same time, you should take into account the inherent trade-offs concerning SPL (especially at the bottom end) in any speaker at this price level.

It is hard to be so enthusiastic about the DM220 - there are some 'wrong qualities' in the sound, particularly at high levels, and the concept of using two drivers to double up LF PHC is one fraught with difficulties. B&W have a good reputation for the reproduction of classical music in the home, but all this is easy stuff. The challenge of Rock monitors is a different ball-game altogether, and a greater knowledge of Rock monitoring requirements would not go amiss.

In particular, the effects of compression and voice coil heating on the sound quality at high SPLs should receive greater attention. The claimed 'high' sensitivity and the 'digital' label should also be set in perspective. Many studio monitors will handle 10 to 100 times the acoustic power, and exhibit 6 to 15dB higher sensitivities to boot. And all monitoring speakers have to handle raw sound, at some time or other. Having said that, the DM110/220 are of above average sensitivity when viewed in the context of their own peer group, wherein many competing models exhibit sensitivities in the 85 to 88dB/1W/1m region.

Shortform Specification

  DM110 DM220
Power handling capacity (PHC) 75 watts 100 watts
Sensitivity 90dB/1W/1m 90dB/1W/1m
Frequency response (-3dB) 70Hz to 20kHz 53Hz to 20kHz
Dimensions (HxWxD) 490x260x250mm 680x290x320mm
Weight 8.7kgs 15.1kgs


Prices: DM110 £119.90, DM220 £199.90 including stands and VAT.

(Contact Details)



Previous Article in this issue

Roland SDE1000 Digital Delay

Next article in this issue

HH V200 MOSFET Amp


Home & Studio Recording - Copyright: Music Maker Publications (UK), Future Publishing.

 

Home & Studio Recording - Mar 1984

Gear in this article:

Monitors/Speakers > B&W > DM110

Monitors/Speakers > B&W > DM220

Review by Ben Duncan

Previous article in this issue:

> Roland SDE1000 Digital Delay...

Next article in this issue:

> HH V200 MOSFET Amp


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