ct0517:
This is what I have on the DM70’s so far from different sources.
https://1drv.ms/f/s!AsdR4rYZVpE4sUzCKIvZoEG9f5Ag Sorry, but there may be duplicates and it includes what I got using the link that you provided
I like this in particular, as there is a very long explanation about their development:
https://1drv.ms/b/s!AsdR4rYZVpE4sDU7GJjlvhBf1_2N I note that a later equivalent for 1974 is much shorter and more simple.
This tells me they need really good setup or people will hear 50hz - 15khz (or less) with an average setup
My treble issues also show up when I use an amp that previously worked OK with these speakers, so it seems that there is some issue with my speakers.
I talked to One Thing Audio who suggested that I get the ’energiser’ units serviced as a first step.
They said that it is very common for the diodes to fail and that they would replace them all as a matter of course. If that does not work I will send in the panels for repair.
My feeling is if B&W kept producing them, the ESL panel would have grown in size - taller, as ESL Panels become more efficient with size.
I am not so sure, as making the panels taller would change the dispersion pattern.
Their horizontal dispersion is also quite good due to the curve used.
B&W did say, however, that a vertical arrangement was tried.
Hope this is of interest
Ian