I would say the mp3 has some low frequency at high volume your speaker can't
handle. A roll off @ 50Hz is not a sub to my thinking, my old Marantz
bookshelf mini-monitors rolled off at 43Hz, my current IPL TL4's are flat
down 30Hz.
Have a search on Google, I'm sure you could find a swept or better still
spot frequency mp3 so you can judge whats happening low down.

--
Pete Cross

"Dave W." wrote in message
...
It sounds like your sub HAS got something loose inside. If this
problem was from the signal, the rattling noise wouldn't come from the
sub, but the main speakers. Probably not the end of the world though -
open it up and have a look - a loose screw is favourite.

d
Pearce Consulting
http://www.pearce.uk.com

Yes, thanks Don. Confirmed with another track which the sub has handled
without problems in the past. As you say, no harm in looking. I know my
limitations.

Dave W.

Yep, had a look. Everthing tidy and well secured in there. Of course it's
just out of warranty. I feel a bit put out because it's never been driven
at
party levels, me being an old git who gives a damn about his neighbours.
Not
sure it's broke though. For the moment, I've just adjusted the roll-off
down
a tad to 50 Hz. Seems to behaving itself so far. We'll see.

Dave W.