It may well be that there are some holes in the dust protection and debris
has taken its toll.
One might wont to bite the bullet and get something different.
Some speakers last forever almost, but it seems to depend on the materials
used for the suspension and dust covers. I still have nice sounding Tannoy
dual concentric from the late 60s, but later model Missions of a friend have
had serious problems in the rubbing area!
Some lowthers have had to be totally renovated.
Interestingly a pair of budget Wharfdales from the 60s still work remarkably
well!
Brian

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"Don Pearce" wrote in message
news:49a73780.1392939515@localhost...
On Fri, 20 Feb 2009 22:18:58 GMT, Rob
wrote:

I think one of my Dynaudio Contour 1.1 speakers has a fault. On music it
sounds as though something's rattling inside, or one of the drivers is
loose. I've taken the woofer out and it looks OK, insofar as I know what
OK is - nothing burnt or blown.

It's difficult to replicate with music, so I recorded a tone and this is
what it sounds like:

http://patchoulian.googlepages.com/speaker

It's a 500kB mp3 file.

Short of contacting Dynaudio and asking about a replacement woofer, any
suggestions?

Thanks, Rob

Sometimes the cone suspension can sag a bit, allowing the voice coil
to rub against the magnet. The way to fix this is to rotate the
speaker 180 degrees before you bolt it back in, so it can sag back the
other way again. If that doesn't fix it, then in all probability the
coil has overheated and some turns have lifted and got loose.

The waveform from the other speaker is none too special either, I have
to say. Have they had a hard life?

d