Car Stereos: Replaced woofers, blown speakers, multimeter

Question
A friend of mine replaced his blown speakers (12 woofers), with some of my older MTX 6000 woofers. The old speakers worked fine until the one blew, now with the MTX woofers installed every time he turns up the volume the fuses (2) in the amp blow.

Answer
Hi Michael,

One of two things are going on here.

Either the subwoofers that've been put in place are shot (you can test this with a multimeter.. ensure that the connection across the wires being sent to the amplifier (WHILE DISCONNECTED FROM THE AMPLIFIER) are equal to or HIGHER than the impedance the amplifier is designed to handle.

Alternatively, the amplifier is fried.

Justin