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B&W DM70's - top end lacking

I have a pair of DM70’s.
They sound really good with vocal, blues and opera.
The bass is overblown with complex orchestral or progressive.

I am already replacing the bass units with Leak sandwich, as I found that the original units had not been repaired correctly.
They had some sort of home made surround made of thick paper with a 12 inch foam surround stuck on top.
The leaks seem to solve some of the bass issues.
I will get the bass units professionally repaired at some point.

Now to the treble units.
The mid and lower treble seems great, but things like symbols seem muted.
I was told that the electrostatic units had been repaired by One Thing, but now I am not so sure.

I am driving them with an Art Audio Quintet fed from a Conrad Johnson PV9a pre.
My CD is a Unison Unico and I am using a Focus One turntable just now.
Cables are from Chord. (Yes they do help a bit)

These are frustrating speakers, as when at their best, they sound so good.
First I need to know what to expect (especially from the treble).
Then I need to know how to fix any issues.

Sometimes they sound so so good and other times . . .
iscm
dylanthecat
11 posts
 
Hi Ian,

The other foams have arrived. They are the correct size. I will probably change them over at some point in the near future.

Best regards, Martin
iscm OP
40 posts
 
I may have a go myself with new surrounds if I can sort out the ’pinging’ in one of the bass units.

Now I bought a sound level Meter and have been checking the frequency response.
There is quite a hump at 112Hz of about 8db.
Perhaps I could try adjusting the filling.
There is also a big drop at 60Hz.
Some more filling may help.

dylanthecat
11 posts
 
Hi Ian,

What meter are you using? I do have a vintage frequency generator but not a meter.

I know that there are several apps available.

Many thanks, Martin
dylanthecat
11 posts
 
Hi Ian,
I have downloaded a few apps that were recommended on the internet. They appear to largely correlate with each other.
I am not seeing any obvious concerns. There is a very minor dip at 35Hz though it is very minor indeed. Nothing to cause concern or requiring remedy I would suggest. M
pepler
30 posts
 
Hello Gentlemen,
I too own a pair of DM-70s I am powering mine with mine with McIntosh MC30s.  The sound is amazing!  When I first heard them the bass seemed overbearing, but after some investigation I found the mounting nuts to be lose.  I tightened them and replaced the gasket on the back panel and all is well.  My bass units have been refoamed.
Cheers, Mike
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