Without question, my obsession with symmetry and fears of getting things wrong has always prompted me to make sure my speaker cables were exactly the same length.
Down to the inch.
But does that make sense? Would a 1-foot difference between the two make a sonic difference?
Technically speaking I do not believe so.
As an experiment, I recently tried just that. A 3-foot cable on the left channel vs. a 6-foot cable on the right. I swear I could hear a difference. The left channel sounded more alive.
Then, I swapped the two. That aliveness did not move.
Hmmmmmm.
I was still unsettled until I closed my eyes and relaxed. Turns out that for me the differences I perceived were all in my head. The small difference in cable length bothered a number of centers in my brain: symmetry and balance among them.
Turning off the affected sensors did the trick.
I am certain that with a big length difference we'd need to worry. However, best I can tell, it's not something we need concern ourselves with.
