B&W DM70's - top end lacking

Thanks  roberjerman
I am not ready to ditch them yet.
The leak bass units work OK now and I am sure that the surrounds on the original bass units can be fixed.

I really wanted to know from an owner what to expect from the treble and if mine need to be redone.
The boxes are in exceptional condition and not beaten up at all, but I did not want to pay for an electrostatic rebuild if it was not required.

Hi Iscm

Well I never thought I would come across another owner of these speakers here. :^)

A few things I found for optimum setup and assuming your speakers are functional.

First are your’s version one or two? The recommended amp 25 - 100 watts. I would recommend at least 100 wpc due to that woofer. If using Solid State make sure its wattage doubles at 4 ohms as they dip to 4 ohms. The amplifier you are using appears to be 15 wpc - This is not enough to hear what they can do.
That appears to be problem one. You need more power.

Floor Setup
These speakers do not have matrix bracing so they MUST not be placed "as is" on a suspended wood floor. if they are on a suspended wood floor your description of

"the bass is overblown with complex orchestral or progressive"

is pretty accurate.

Solution.
They must be raised on a solid platform, to where the tweeter panel is level with your ears. This fixes two aspects.

It ensures the bass stays tight and clean, and the ESL panel is the most resolving. They like a larger space, do not put them up against walls. They should be free standing.  

Pic 21 on my virtual system shows how I had them setup.

B&W ESL DM70

I used them with and without external tweeters. If your room is heavily damped you may need external tweeters. They are the total opposite of B&W 801’s, in that they like an un damped room just like my Quad 57’s.

The thin curved ESL panel needs to be at ear level, but its shape does give a decent sized sweetspot.

Any ESL repair shop can fix the speakers if they need repairs.

Hope this helps. .

Hi  ct0517
Thanks for the reply.
These speakers are something special.
I have the original MK1's.

My room has stone floor (with thick fitted carpet) and stone walls.
I would say that the room is heavily damped and has very low ceilings.

The change of bass unit to the 13 in Leak Sandwich has helped quite a lot.
I was using a Quad 306 as my power, but that could not control the bass at all and in fact the Art Audio is much better in that regard even though it is not so powerful.
It has the option of Ultra Linear at 25 W with variable feedback
My volume requirement is not so loud these days.
One of the reasons for changing to the tube amp is just how much more musical the system sounds especially with Blues and Jazz.

I just want to tame the bass a bit and get the treble balance right.
Sometime I wonder if I have sometimes a voltage problem, as about 80 homes were just built near me in our small village.
The mains transformer did blow up about a month ago and when that was replaced I seemed to get louder treble.
Is it possible that I was not getting enough voltage to the Electrostatic panel? 
The treble sometimes seems to go down a bit at peak times.

ct0517
I see how you have raised your speakers and I did think about doing the same. On my speakers it could be done between the existing stands and the main box, say 6 inches (15cm) should do, I think.

It is strange, as this evening, most of the bass issue seems to be gone. The treble is right up which what makes me think about checking my mains.

Have you ever noticed your speakers sometimes sounding much better than at other times?

iscm -  I found the panels sounded best at ear level and by raising the speaker to achieve this, the bass improved as well. I have a device that gives voltage readout. Plugging components into it also shows how much voltage they are using. Any voltmeter can be used to check AC voltage on the mains. When it sounds good and when you notice a problem. If there is a difference that tells you something is up with your main. But if the mains voltage is good both ways, I would suspect an issue with the power supply in the cabinet so it should be looked at. That is not a difficult repair.