Don Pearce wrote:
On Sat, 21 Feb 2009 14:18:48 GMT, Rob
wrote:

Phil Allison wrote:
"Rob"
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.

** Sounds like the voice coil has partially detached from the cone and is
hammering in time with the low frequency tone.


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

** Run the test with the driver removed and see if you get the same
distorted tone.

OK - it still buzzes, but less loudly. I've put a sample on the web page.

Check for any object caught in the back of the frame or held by the
magnet.

Can't see anything - thanks anyway. The only thing that looks slightly
odd is what looks like a line drawn on the yellow cloth bit behind the
cone - but I'd guess that was some sort of manufacturing marker.

Rob

That's odd. I would expect the buzz to increase noticeably when you
take the speaker out, because the cone will be moving further.

Nope, just tried with a number of different tones. The buzz becomes
similar in volume in/out as the tones get higher. It's a ported cabinet
if that makes a difference.

This is
almost as if the cause of the buzz is more to do with the cabinet than
the driver. Any way you can pursue that? Perhaps swap drivers between
cabinets and see of the problem swaps as well...


Ah, I would if it wasn't for the probability they'll be going back to
Dynaudio. If it's obvious they've been tampered with they'd be less
likely to offer any concession. I'd fit a new driver myself, but it
seems there is just no way to source drivers from anyone else. Thanks
for the idea though.

rob