It means as long as the positive terminal of the speakers are hooked to either the positive or the negative you should be ok. The signal to the speaker is A/C just like an appliance polarity is only important in that you have both speakers hooked up the same way so the sound waves don't cancel each other out. Sure your absolute phase will be off 180 degrees if you hook both of them up backwards, but give it a listen, not sure you will be able to tell.