Originally Posted by MichiganMadDog
do speakers loose some ohms with use?
Overheating a coil can melt its insulation and cause shorts. Otherwise, no.
As noted above, it sounds like you measured DC resistance rather than impedance. Speakers are complex impedance devices, so they have both a resistive component that can be measured easily with a multimeter, and an inductive reactance, which is frequency dependent, and does not affect the circuit's behavior with DC power. Impedance is a vector sum of the two, so it is lower when the reactance is 0.