junkyarddog

first of all....how can a speaker coil have a + and - side?? and what is that thing that stereo shops use to test polarity of speaker coils and how does it work?

Allan

A 9 volt battery. If the speaker pops out, you're good. You got the + and - right. If it pops in, you got it backwards.

junkyarddog

the coil magnetizes the cone and moves it.....ofcourse it has a + and - side....but is it really strait from a 9 volt? that seems like it would destroy some smaller speakers.

Allan

I generally use that for subs. i guess you're right on the smaller speakers. Usually, my smaller speakers are marked. i only had to do that battery trick w/ my subs. don't hold the battery to the posts long. just to check it move and that's it. it'll pop in or out

Jim85IROC

iTrader: (2)

I've tested the polarity on hundreds of small speakers, as small as 3.5" with a whizzer cone, and I haven't blown any yet. A 9 volt battery has very little current capacity, plus if you figure 9 volts through a 4 ohm speaker, that's about 20 watts, but that requires 2.25 amps of current, which that 9 volt can't get anywhere near.