Probably the Red one, but as long as you stay consistent between all the speakers, you'll be fine. After you're done, use a test disc to check phase between speaker pairs. If they are out of phase, simply switch the wires.
Confession: The red stripe on the black wire was nothng more of the red part of the wire being stuck to the black wire , when the wires were pulled apart. Thats the first mistake I ever made. LOL:whistling:
Speakers' audio signals are rapidly alternating voltages, not a fixed positive and negative like a battery. However, you usually need to keep them in-phase, so the red binding post on the amp for each speaker needs to be connected to the red binding post on its speaker, and the amp's black binding post connected to the speaker's black one.
A battery, however, can be a good way to pulse a speaker to test phasing. If you touch the leads briefly to a battery and watch the direction the cone moves, you can identify phasing. Reverse the battery and it will move in the other direction.
I am pretty sure when you connect the positive terminal of a battery to the positive terminal of the speaker it should produce an 'outward' motion on the cone... the cone should move away from the magnet of the speaker
I'd agree that the 'absolute phase' of the system is of little importance; however for impulse type of sound, for example a kick drum or something I could see absolute phase making a difference...
absolute phase is a 'sticky' subject though there is some info/research on the topic at the end of this article that you may find interesting: http://www.stereophile.com/asweseeit/988awsi/index1.html ... it has some decent reasoning why absolute phase can be perceived in some cases; for the most part I agree though that it does not matter