Originally Posted by Bill Fitzmaurice
No. For the difference in the lengths of wire used to be so drastically different that it was the slightest bit audible the speaker placement would have to be so poor that the difference made by the wire would be the least of your problems.
If you really want to be picky, you can place your speakers in the optimum position, which would likely mean that they are not all the same distance from the amp(s) driving them, but still cut all of your speaker cables to the same length. A little extra slack in the ones that could have been shorter won't hurt anything.
I cut the speaker wire for my LCR speakers all the same length, even though I could have cut the center and right cables a couple feet shorter. I did the same with my surround speakers (though they are a good 20 feet longer than the ones going to my LCR's). Even though I doubt there is an audible difference, it's nice to have them the same length for a few other reasons...
1) Once you have determined what the longest length you need for your LCR's is, you can simply cut the others the same length rather than measure each one out separately. This saves time and, unless you're longest run is significantly longer than your shortest run could have been and this extra length makes the difference between having to buy another spool of wire or not, I wouldn't sweat it.
2) Less chance of making a mistake and connecting a shorter cable to the speaker where you would need the longer cable. If they're all the same length then you can't get that part wrong, at least. Of coarse, you still need to make sure that the wire connected to your left speaker is the one that you are connecting to the Left terminals on your amp, etc. And you still need to make sure you haven't reversed the polarity (though I believe some AVR's are capable of detecting when you have your speakers wired out of phase and can correct this internally).
3) Most importantly, having them all the same length gives you the flexibility to move your amp from one side of the room to the other without having to swap speaker cables around or cut new ones. When you originally set your room up, you might have your amp on the left side of the room. Inevitably, a year later, your spouse will want to rearrange furniture and move it to the right side of the room. As long as they don't want it moved from the front of the room to the back or vice versa, you'll be ok.