I suspect that the 3-way Alpine SPX speakers that I had installed are
not all in phase. Normally, to test polarity, I'd hook a 9volt battery
up to the speaker wires normally going into the amp. Each speaker
should either pop out or pull in, but all should do the same thing,
assuming positive and negative are hooked up correctly.

HOWEVER, these 3way speakers have not one but two crossovers that like
to absorb the 9v and prevent the speakers from moving.

How else can I test the polarity? Do I simply need to add more 9volts
into the equation, and if so, how many, and how many would it take to
accidentally fry my crossovers?

Thanks!