B&W DM-7 experience?

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Stevemaine

New Member
Hi all-
So, here's the deal. I'm strictly a headphone guy (girlfriend doesn't like my tunes), but I'm thinking of setting up a system with speakers. I don't know much about speakers really, but I like vintage stuff. I have a line on a pair of BW DM-7 (mark1 I think) which I like the look of. Seller says one tweeter seems weak, and I see getting a replacement would be tough. The only other thing I know is that they require some pretty serious power, which I'd have to come up with. I listen mainly to jazz fusion and female vocal and I'm kind of a bass head.

Anyone have some personal knowledge and impressions of this speaker?
 
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Hi Steve, The DM-7's are great speakers!
I found my tweeters a bit dull sounding and upon close inspection, I found that the coating on the dome was thinning out and allowing the dome to become filled with tiny little holes.
I cleaned off most of the dust and coated the dome with "Vintage AR" sealant. The official surround coating for AR and KLH fabric surrounds.
My tweeters woke up after that!
 
Hey, thanks for the feedback. Much appreciated. It will be about a 4 hour round trip to get them (after the current ice storm stops). These speakers have the white cabinets, which I imagine were less common than the wood veneer. One other question. Does the fact that they have the adjustment knob on top make them a Mark1?
 
So, I picked up the DM7's over the weekend. They needed some scrubbing, but look pretty good. Surrounds look recent, but not sure. The one noticeable thing is that one has the original dome style dust cap and the other has a fairly flat fabric type. That
speaker also has glue showing around the surround that sure wasn't original, so it looks like they had some work done. I have yet to hook them up and see what the tweeter issue was. The previous owner felt the contour adjustment switch may need cleaning. I've only come across one other pair in white cabinets. For $75 (pair), I'm pleased so far. What kind of power do I need to bring out the abilities?


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DM7 was the first real speaker I've ever heard, I was probably 9 visiting a distant Uncle, His DM7's were playing some jazz and big band music and I remember thinking it sounded like the band was right there in the house. I chased the experience of that memory for many years. The same Uncle gave me his homemade Bogen DB-20df 3 or 4 years later and I build a single speaker with radio shack drivers for it.
 
That's great to have those kind of memories. I've seen a few stories like that of the DM7's leaving a real impression. I'm really looking forward to trying them out. I don't seem to have any friends or family that is into this stuff at all. Girlfriend keeps wondering why I need more than one pair of headphones. I'm just cleaning up a nice (but filthy) Pioneer CT-F8282 casstette deck I found at Goodwill for $6. Love this stuff.
 
So, I finally gave the speakers a quick test and I have to say they sound very natural and nice. The only problem I hear so far is that vocals sound a bit distant and hollow. I have a question for those who know these speakers. Are the tweeter housings (under the screen dome) meant to be rotated? I noticed these do, but didn't know if maybe the mounting was just loose.
 
I bought a pair of DM7s new in 1978. Can't fault them. Mine were mkI like yours but with walnut veneer. Very vulnerable to being over driven, especially by a clipping amp(obviously, but especially so with these). You need at least a 200wpch amp imo. I wouldn't push them much further, though. I paired them with a 1st gen NAD 90wpch receiver which promptly fried the drivers because it had zero headroom and although I didn't overdrive the amp by much at all, it didn't take long. I was unaware the NAD had no headroom. So be careful.

Do you mean rotate as in toe-in? I would toe-in the cabs since the woofers are responsible for mid range.
 
Good to know about powering them. All I have at the moment is a Rotel 1060 amp. On mine, if I remove the screen domes, the entire tweeter housing and plastic base spin around freely. I didn't see anything in the manual regarding this.
 
Wow, thos look cool. Love the white finish. Would go great with our MCM stylings.
Grilles?

I wish I could help on your questions but I only recently started reading up on the DM line. There is a pair of DM2's available near here, but the price is too high. I will tell you though, if you are going to try and jump up to 200 watt power range, unless you find some other score, a great place to go will be an Adcom GFA 555 or 5500. Personally I feel they are about the best value $/watt available at right about $2/watt.
 
Stevemaine said:
Good to know about powering them. All I have at the moment is a Rotel 1060 amp. On mine, if I remove the screen domes, the entire tweeter housing and plastic base spin around freely. I didn't see anything in the manual regarding this.
Click to expand...
Might need to be tightened up from inside the cab?
 
Nope, not supposed to rotate. The tweeter base has a pin that fits into a hole in the cabinet. One of mine was broken, too. Tighten the tweets up a bit from inside.
 
I really like the white finish too. Very contemporary looking for a vintage speaker. I do see Adcom amps on CL around here quite often, but didn't know much about the brand. I'll keep an eye out.

I'm kind of thinking the tweeters need tightening too, but I guess I'll see what other comments I get. Seemed like it would be a good source for rattles.
 
The weak tweeter might be a tough one. SOmeone might know more specifics about that particular one and it's tendencies. If it is available/repairable etc. Also, some chance it is the controlling cap in teh crossover getting old/bad, or the adjustment pot. Have you looked into those adjustments to see if they can be cleaned with deoxit?
Do some searches for that and the other DM models to look for similar applications and issues others have had and delt with and maybe there are some hints. Search for B&W DM in the Speaker section only

This thread has some literature on them in the OP.
http://audiokarma.org/forums/index.php?threads/b-w-dm-7.201244/
 
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I think you're right about the tweeter being a tough one. I've seen others mention problems, which some have managed to solve with fairly simple procedures, but I never seem to get lucky that way. That speaker has some corrosion on the top aluminum plate as if it has seen some moisture at some point. I may try cleaning the contour pot first and see what happens. It isn't completely dead, just not as bright as the other. I know someone (someplace) mention recoating the diaphram with some kind of vintage speaker dope/sealer, but I don't know what that is, where you get it, or how you know if you need it. Just the beginning of my education...
 
I used to have the DM7. Drove them with an HK Citation 16a, but a Threshold Stasis 3 seriously embarrassed it. This was back in '83.

Apart from checking the tweeter DCR, the contour control might need to be looked at. I eventually bypassed it in mine as I never used it.
 
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