Well, finally got time this afternoon to do the ABX testing.
Wire compared was Axiom's 12ga speaker wire versus Leviton SJ 2/16 LL26332 (as imprinted on jacket) extension cord - 16ga. 2 conductor... lengths were 7' 6" (+/-1" by the time they were stripped and prepared). Music selection (since I found out - disturbingly - that he's a Sarah McLachlin fan) was David Foster - Man in Motion.
First off, we did a "bias test"... this is A - Axiom wire, this is B - the Leviton... he wholeheartedly agreed that A was, in fact, better.
Secondly we did a single-blind ABX test. Ten samples, in each case, he determined the audio levels, the portion of the track to listen to, and the listening length and cable to listen to (A, B or X). He correctly determined the unknown cable 4 out of 10 times.
All throughout the test (all ten samples) he made the subjective analysis that B sounded clearer and brighter, so he was especially shocked to hear that B was the Leviton during the first 5 tests and the Axiom during the second half, proving that his perception was skewed.
Though we did further torture testing whereby I spliced together "Frankencable" by twisting together 5 different pieces of assorted cable I had around, about 18" apiece of the Leviton, some pink 12ga. "speaker wire", 14ga. Romex, Cat3 (separate hunks - 8 conductors for +, 8 for -) and some 18ga. "primary wire" that I had. Each splice was lovingly twisted together in a matter of a few seconds with a pair of Craftsman linesmans pliers and taped with red 3M electrical tape. We did observe that at reasonable listening levels, Frankencable and the Axiom were interchangable, however the Frankencable did exhibit more audible distortion at a lower level (at -32dB reading on the volume control, rather than -30dB)
After all the testing by ear, the equipment came out in the form of an SPL meter (thanks, Dennis!) - one interesting tidbit was the resistance of the Leviton cable was increased with the amount of oxidation on the cable - I mean this was NASTY, it was stored in a damp basement for about 9 years, I'd refer to the conductor colour as brown, and it wasn't cleaned off before the tests. Afterwards the SPL meter did indicate a difference of ~0.5 dB SPL between this heavily oxidized cable and the Axiom cable (full spectrum pink noise @ 75dB SPL reference), but this difference disappeared once the cable was cut back to expose moderately clean copper (which technically also shortened the cable by ~ 3in)
So, again... the copper at these run lengths were impossible to distinguish, even giving up 4AWG sizes and a LOT of oxidation... and only oxidation was a factor (to instruments only, not to the naked ear) in affecting sound quality.
Now, boutique cable guys, start up those skeptical machines... anything short of a time machine which allows for identical variables will still leave a little seed of doubt in your mind (already my brother suggested that the subjects hearing must be flawed and that he'd be able to hear the difference given THAT big a discrepancy between cable - after all, he had to deal with nearly identical wire during HIS ABX... so another of these might be in the works)
Didn't have time for me to sit in the listener's chair today, since the subject took as long as he needed to make comparisons, but last time I took a single blind, I scored the same (4 - 6/10).
Bren R.
