I find it incredibly useful to get a DATS unit and measure the impedance curve of the speaker. You can also if you are handy do the same with Room EQ Wizard and a home made jig.
Doing a full impedance sweep is often incredibly useful, and reveals any shorts or open circuits in either the crossovers or drivers.
Also, if it helps, I’ve had Focal drivers stop working because of too much stress on a coil. The PCB mounted coils would break almost invisibly at the PCB.

