In my experience, in every marriage or living-together relationship there is one partner who likes their loudspeakers BIG, and the other who would prefer that loudspeakers didn't really exist. I personally like my speakers on the large side, not for their looks but for the weight of sound they can produce. I am extremely happy with my current home cinema set up of a 50-inch Pioneer Kuro plasma screen (the best TV ever, but sadly no longer made) and my B&W 801 loudspeakers. I used to be married.
What I look for in a pair of loudspeakers can vary. I love Quad electrostatic loudspeakers – all of them since the original ESL57 – for their accuracy, but they really do need a large room to work well. I love my B&W 801's also for what I personally perceive as their accuracy, although I know opinions do differ. I quite often like Tannoy dual-concentrics. They do sound 'speakery', but to me it's a pleasant tone. And in days gone by when top recording studios would have huge horn loudspeakers for monitoring… heaven!
The speakers shown here, up for auction on Ebay at the time of writing (October 5, 2012) I haven't yet heard – unfortunately. But I would very much like to. I have a feeling that the sound they produce will be quite different to any other loudspeaker.
The reason for this is that they combine an electrostatic unit on top for mids and highs, and a conventional moving-coil drive unit for the lows. I believe this will combine the clarity of electrostatics with the weight of a moving-coil woofer.
The B&W (Bowers & Wilkins) DM70 was first produced around 1970. B&W's own data sheet states that, “The DM70 is new thinking on acoustical distribution pattern especially within the vitally important mid-frequency region of 400 Hz to 5 kHz, aiming towards exploring the advantage of an approximately spherical distribution pattern.”
And also, “The styling and general appearance has been designed to be acceptable in the world market, resulting in the Standard and Continental versions each available in various finishes.”
As I said, these loudspeakers are quite large, at 82 x 68 x 39 cm, not including the stands. And they are pretty heavy at 34 kg each. Don't go lifting them on your own.
It isn't really possible to assess the sound of a loudspeaker from the specifications, but it is interesting to see the frequency response, and also the polar response (click the image for a larger version)…
Although there is some pixelation in the image, it is possible to make out that the 10 kHz polar curve has an amazingly wide distribution. It isn't clear why the 5 kHz (if I read it correctly) response has teeth like a gear wheel, but it might be advisable not to move your head from side-to-side too much.
Perhaps what interests me most about these loudspeakers is that they have a quirky kind of beauty. They are most definitely not the norm in loudspeakers, and the polished walnut cabinets (other finishes were available) make them look like they should be on Antiques Roadshow as fine pieces of furniture.
Why B&W chose not to continue marrying electrostatic and moving coil drive units, I don't know. I suspect however it has something to do with manufacturing cost. Even so, it's an interesting piece of audio history. If anyone has a pair in Oxfordshire and would like to invite me over to listen, I'll bring the beers!
Don't forget to take a look at the Ebay listing if you read this in time.