Trying to repair the DM5
I bought a pair of vintage dm5 speakers which were part of the legendary series Bowers&Wilkins made in the seventies. (DM = Domestic Monitor). I paid €110 (about $120?).
The dm5 is between bookshelf and floorstanding and, for its small size, it has amazing strength especially in the low range.
However, the previous owner didn’t tell me about the issues with one of the speakers. He just said that “they sounded allright”. Which they didn’t. Or better one didn’t.
The faulty one produced a loud, kind of flapping noise from the woofer. Obviously, this was something to be looked into. I never opened a hifi speaker before.
We tried our luck. We = my wife and I.
One of the woofer driver screws appeared to be blocked ànd loose at the same time. Could this cause the chattering noise ?
Meanwhile, we had already glued a little hole we discovered in the heart of the woofer cone. You never know. But no, noise still there.
Now we had to drill out the blocked screw and see what was happening inside of the enclosure: masses of dampening wool-like stuff, some connecting wires in good condition, the strange backside of the woofer cone, clusters of white corrosive dots, but nothing whatsoever that would cause the loud noise.
We noticed that pressing our fingers hard on the empty screw holes while playing music, diminished the noise which could mean nothing was wrong with the crossovers or the wires or the dampening material.
So far, so good. Now we must find the right screw (or a lookalike) to replace the one which was used in 1978. More on this later…