Voice coil unwound!

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   I've come across an 18" where if you look through the vent holes in the rear of the magnet you can actually see the voice cool has come completely unwound! If you shake the driver it sounds you're tipping a bag of skittles up side down

Is this too much average power level abuse or potentially mechanical failure of sorts?

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Grubbah Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 14 July 2011 Location: Portsmouth Status: Offline Points: 2014	Post Options Post Reply Quote Grubbah Report Post Thanks(0) Quote Reply Topic: Voice coil unwound! Posted: 09 March 2016 at 8:40pm
	I've come across an 18" where if you look through the vent holes in the rear of the magnet you can actually see the voice cool has come completely unwound! If you shake the driver it sounds you're tipping a bag of skittles up side down Is this too much average power level abuse or potentially mechanical failure of sorts?

madboffin Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1532	Post Options Post Reply Quote madboffin Report Post Thanks(0) Quote Reply Posted: 09 March 2016 at 8:48pm
	If the wire has fallen off the coil former, it usually means the glue has failed due to overheating, caused by too much sustained power. Sometimes it's a manufacturing defect, i.e the glue wasn't properly cured.

mark_in_manc Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 13 February 2016 Location: Manchester UK Status: Offline Points: 15	Post Options Post Reply Quote mark_in_manc Report Post Thanks(0) Quote Reply Posted: 10 March 2016 at 2:14pm
	Sounds like overheating to me too. A pure mechanical failure might result from momentary excitation by a very large, impulsive signal which did not contain enough power to heat the coil up - but you'd not expect this to part the coil from the former. It might part the former from the cone! :)