Determining speaker polarity

[da na]

Is there a reliable method of determining speaker polarity via a multimeter or other tool?

I use Sansui S-3000-2 compression horns to build quarter-scale replicas of Voice of the Theatre cabinets. Only issue is, the horn has two wires - blue and black - but the terminal the black wire connects to is marked with red paint on the speaker. As such, I am not sure if the black wire or the blue wire is the positive, so I'd like to confirm for sure. I could pull the back off the horn assembly and look inside, but due to the extremely fragile nature of tiny compression drivers' guts, I would be afraid to snap a tiny wire or tear the diaphragm somehow. 

[WhitetailAni]

59 minutes ago, da na said:

Is there a reliable method of determining speaker polarity via a multimeter or other tool?

I use Sansui S-3000-2 compression horns to build quarter-scale replicas of Voice of the Theatre cabinets. Only issue is, the horn has two wires - blue and black - but the terminal the black wire connects to is marked with red paint on the speaker. As such, I am not sure if the black wire or the blue wire is the positive, so I'd like to confirm for sure. I could pull the back off the horn assembly and look inside, but due to the extremely fragile nature of tiny compression drivers' guts, I would be afraid to snap a tiny wire or tear the diaphragm somehow. 

Unless there's some circuitry involved before the speaker driver, you can just try it both ways and see which sounds better. Flipping polarity doesn't hurt it, it just causes the speaker to take a hit to audio quality and volume as it's now firing in reverse (sort of)

[Levent]

Back in my age days, I used to plop 9v batteries to each terminal to see how much of a noise (more like a pop) made to find out polarity. Not sure if it was the correct move lol

[da na]

13 minutes ago, WhitetailAni said:

Unless there's some circuitry involved before the speaker driver, you can just try it both ways and see which sounds better. Flipping polarity doesn't hurt it, it just causes the speaker to take a hit to audio quality and volume as it's now firing in reverse (sort of)

Yeah that's what I would typically do, but that is really tricky with a compression horn. The actual diaphragm is probably the size you'd find in a good pair of IEMs, albeit with a much larger magnet - the actual driver moves a tiny amount of air which is then amplified by the horn. Since the work the driver does is so incredibly small, I can't discern any difference from the polarity.

[da na]

8 minutes ago, Levent said:

Back in my age days, I used to plop 9v batteries to each terminal to see how much of a noise (more like a pop) made to find out polarity. Not sure if it was the correct move lol

I've also done that on massive speakers but the tiny sensitive coil of the compression driver would instantly vaporize from a whopping nine volts

[Bitter]

So bare driver with no cabinet or cross over? It honestly might not be polarity sensitive in regards to sounding different but you want it in the same phase as the rest of the speakers playing. If you have two of them connect both opposite phase and play some in phase out of phase audio test tracks and see which sounds correct then see what sounds correct with the rest of the speakers.

[da na]

19 minutes ago, Bitter said:

So bare driver with no cabinet or cross over? It honestly might not be polarity sensitive in regards to sounding different but you want it in the same phase as the rest of the speakers playing. If you have two of them connect both opposite phase and play some in phase out of phase audio test tracks and see which sounds correct then see what sounds correct with the rest of the speakers.

I've got a cabinet and crossover, but neither original to the speaker system which it came out of. 

Great suggestion with the phase, I'll try that.

[Bitter]

9 hours ago, da na said:

I've got a cabinet and crossover, but neither original to the speaker system which it came out of. 

Great suggestion with the phase, I'll try that.

If the cross over has polarized caps then that could be a clue too.