Re: What\'s different about speaker wire?
In theory there are differences, in practice the claims are more than a little suspect. As far circuit analysis goes, audio frequencies are effectively DC. The AC transient effects happen so rapidly (they are over in a few hundred nanoseconds, and at 20Khz, the fastest events are measured in tens of microseconds). In theory the skin effect would make a stranded conductor more attractive, in practice at 20khz, the skin depth is likely to be far far larger than the diameter of strands, so while the effect is real the wire strand is so much smaller than the skin depth, it is meaningless. Get to 20Mhz, and it certainly does make a difference, but not as 20 Khz.
About the only thing that counts in speaker cabling is DC resistance, the reactive components are two small to care about in the wiring.
So if you want to run 100 watts into an 8 ohm speaker, you are going to have to deliver about 3.5 amps,or 5 amps with 4 ohms. At 8 ohms,3.5 amps is about 30 volts, so anything that is insulated well enough to use as line cord is more than adequate. What you want to look out for are loses in the line. The loss is I^2 R, so for the 8 ohm load, at 100 watts, each ohm resistance in the line to the speakers will result in about 12 watts loss, and a reduction in the power delivered to speaker (i.e. 2 ohms in the line makes an 8 speaker a 10 ohm load). At 4 ohms, each ohm in the line is 25 watts! So while 16 gauge wire will very easily carry the current for 100 watts, the loss from 20-30 feet is such that you may be expending a fair amount of energy warming the wire. You probably don't want the wire to represent more than about 10% of the load for applicatoins where you are talking about more than a few watts. That suggests that for you need to look up the resistance of various wire sizes per foot, and pick a size accordingly. For the 100 watt example, something like 10 gauge for a 30 foot run would be a better choice than 16 gauge.
