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Multi-Way Conventional loudspeakers with crossovers

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Old 1st March 2013, 08:46 PM   #11
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Old 1st March 2013, 08:49 PM   #12
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Old 1st March 2013, 08:56 PM   #13
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Following the link to "B&W Group North America Service & Support - Owner's Manuals & Drawings" shows that the DM2 was available from 1973 to 1984 and cost $300; the DM2/II was available from 1978 to 1981 and cost $525 - why?

So far as I can tell, the obvious differences between the two was that the /II used the Coles 4001 in place of the B&W supertweeter and had some adjustment options on the crossover - other than that they seem identical except that the former is most improbably described as a "Bookshelf" speaker whereas the latter is a "Floorstanding" speaker. I don't know what was different about the DM2A other than the shape of the port.

I have now realised that much of the foregoing is utter tosh - the DM2/II seems to be a completely different beast. There seem to have been three different versions of the DM2; what I have described above are the first two versions (I have a pair of each), the port on the third one had rounded edges.

Last edited by surv1v0r; 1st March 2013 at 09:10 PM. Reason: OOPS - realised that the DM2/II was not anything like the DM2s.
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Old 1st March 2013, 09:23 PM   #14
system7 is offline system7  United Kingdom
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I do remember being rather impressed with the B&W DM-2A speakers. Very nice smooth bextrene bass performers that have a considerable fan-base even to this day.

Click the image to open in full size.

This is the earlier DM2:

Click the image to open in full size.

Uploaded with ImageShack.us

I'd think the crossover and 1/8 wavelength transmission line bass loading evolved a bit. But only the supertweeter is really different by the look of it.

I'd incline to renew capacitors with 50V NP electrolytics and resolder some connectors with old leaded solder which you can still buy for personal use at Maplins. Otherwise, where are we going on this?

Oh, FWIW, IIRC that's a B&W 8" bextrene bass and a Celestion HF1300 tweeter. And, IMO, bextrene was best not used above about 2.5kHz, which is possibly part of why these were good speakers.
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Last edited by system7; 1st March 2013 at 09:33 PM.
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Old 2nd March 2013, 02:43 PM   #15
system7 is offline system7  United Kingdom
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Here's the crossover schematic for the B&W DM2 version II speaker.

Hope it helps.
Attached Images
File Type: jpg B&W_DM-2_ver.II_crossover.JPG (102.2 KB, 122 views)
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Old 2nd March 2013, 03:43 PM   #16
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I was working for B&W in 1979 and the only DM2 that I can remember is the one that system7 has posted photos of.

Please don't ask me any technical questions. I was only a part time 17 year old and my job was to take the hundreds of cabinets off a big lorry and pair them up. In those days every speaker was uniquely matched to its pair, I would stand in a large room with hundreds of cabinets and stands and match the random delivery together.

In that era we also had the DM4 which I had, a delightful 3 way - I'll loosely call it a bookshelf but it was realy a standmounter.

The DM7 - a real beauty even today.

There was also a DM6 - a sort of halfway house up to the monstorous 801.

The 801's. The daleks.

There was also the DM1 but you don't hear much about them these days.

After I left the company we started to see speaker series. Today for example we have the DM6XX which covers everything from tiny bookshelf speakers to great big floor mounted speakers. I wonder if that was the case with the DM2. B&W might have found a sucessful menu and built a series of speakers around that idea. Please correct me if I am wrong.

I've always stayed loyal to B&W. I started with the DM4 and eventually upgraded to the DM14. A few years ago I adopted a pair of DM603s2's which after the passing away of my brother-in-law have now been replaced by DM683's.

If I wasn't busy saving for a house I would jump at a pair of 802D's.

Last edited by KatieandDad; 2nd March 2013 at 03:51 PM.
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Old 12th March 2013, 01:33 PM   #17
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Quote:
Originally Posted by system7 View Post
Here's the crossover schematic for the B&W DM2 version II speaker.

Hope it helps.
Thanks for that, I will use it to try and understand the different crossover in my DM2s and to renew the capacitors which I should be able to find on the Falcon Acoustics site.

There is an even earlier version of the DM2s than the images you have posted. It used some unidentifiable Super-tweeter (not the Coles 4001) and the Mid/High unit and the Super-tweeter were place side-by-side. The crossover didn't have the adjustment control that appeared on the later version. I have no idea whether the crossovers were identical apart from the control - I will eventually work that out.

This LINK shows my early version of the B&W DM2 with the Mid/High frequency HF1300 & the unidentified Super-tweeter side-by side below the DW200 bass unit.
This LINK shows the second version, with a Coles 4001 and all three speaker units in line vertically.
This LINK shows the first (white, lamb's wool?) and last (grey) layers of wadding.
This LINK shows the first and intermediate (carpet underlay like) layers of wadding.
This LINK shows the last, coarse and stiff layer of wadding which sadly is now turning to powder.

The cabinets on the later versions I own are VERY beaten about. Rather than trying to refurbish the cabinets, I may try to make an exact (but undamaged) copy. I don't understand the three different types of wadding used or know what I could use to replace the final section nearest the port opening. B&W can't offer me any help.

I have read somewhere that the B&W DM200 bass unit has characteristics very similar to the 8" bextrene coned Kef B1039 but have no idea whether or not that is true?
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Old 12th March 2013, 08:59 PM   #18
tvrgeek is offline tvrgeek  United States
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Ah yes, the DM-2. The first true hi-fi speaker I ever heard. Should I blame them for my addiction? I had JBL's at the time. Then I heard the 104a's, wound up buying DItton 44's. The 44's has BASS!
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Old 7th April 2013, 06:46 PM   #19
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Question What can I use to replace this deteriorating wadding?

I have just realised that the link showing the last, coarse and stiff layer of acoustic wadding on my B&W DM2s was wrong - this is the correct LINK. The material looks and feels rather like a loofah

Unfortunately, as a result of the age of the speakers this wadding is now deteriorating and turning to a fine powder as can be seen to the right of the photo (the base of the port). This tends to spill out of the front of the port.

Does anyone know what I might use to replace it?
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