So here is some anecdotal on "deniers" - those who claim they hear no difference:
A bunch of them were gathered in a blind test, where some speaker cables were to be tested - generic zip cord vs. a high end speaker cable - or so they were told.
Then, the tester used the same exact cable, but, on test "b" (cable "b" to the subjects), the polarity was swapped (speakers connected out of phase).
100% of the subjects reported they heard no difference. Blind. The matter of fact, the out-of-phase "cable" sounded noticeably worse than the correct connection cable.
Go figure!
A bunch of them were gathered in a blind test, where some speaker cables were to be tested - generic zip cord vs. a high end speaker cable - or so they were told.
Then, the tester used the same exact cable, but, on test "b" (cable "b" to the subjects), the polarity was swapped (speakers connected out of phase).
100% of the subjects reported they heard no difference. Blind. The matter of fact, the out-of-phase "cable" sounded noticeably worse than the correct connection cable.
Go figure!