There is no difference in speaker wire. This has been proven again and again in double-blind tests. Unless you've engaged in your own double-blind testing, you cannot say "I hear a difference" with any real confidence. You think you hear a difference. But our senses are easily fooled. You've all experienced optical illusions, right? There are also auditory illusions, touch illusions, smell illusions, taste illusions, etc. That's why the scientific method has been so successful; because it is a tool that gives us the means to bypass our own confirmation biases, agendas, partiality, and the inherent weakness of our own senses.
Allow me to relate a little story. I'm good friends with a brilliant and extremely knowledgeable audio engineer / acoustician here in my hometown. I've learned everything I know about audio and audio engineering from him. He designs his own speakers that sell for five digit prices, he designs recording studios for major labels & artists, and he has incredibly trained and sensitive ears. He's able to hear EQ changes within .5 db increments and can tell you exactly what frequency is poking out of a mix without using a visual cue like a spectral analyzer.
When we were mixing and mastering my progressive rock project (THEO - The Game of Ouroboros), we had to upsample the mixes from the recorded format (24bit, 44.1kHz, tracked at my home studio) to a hi-res format (24bit, 96kHz) for inclusion on the Blu-Ray. We had three choices at our disposal to accomplish this feat and we decided to test each one. The first was using the resampling option in ProTools, which is the DAW that my friend runs at his studio, as it's the industry standard. I believe he was on ProTools 10 at the time. The second option was to upsample in Cubase using it's resampling algorithm, Cubase being the DAW I use. And the third was to feed the analog outputs of my Cubase machine, the machine on which we were doing the mixing since I had already pre-mixed everything at home, into the studio's $14,000 Prism Dream converter, capturing the the audio at the high sample rate.
The ProTools internal upsampling was really bad. We both agreed that it was the worst of the three. Cloudy, with a collapsed stereo field comparatively, and a real lack of punchiness. The Cubase internal upsampling sounded really good. We were both surprised given that ProTools is the industry standard. The re-capture of the audio from the $14k Prism Dream sounded really good, too. In fact, my friend the studio owner claimed it was the best. But I honestly couldn't hear a difference between it and the Cubase internal upsampling.
I took the two tracks home that night, the Cubase internal upsampling track and the Prism Dream track. And I lined them up in Cubase, 100% sample accurate. And I switched between them, closing my eyes and doing a random number of fast button presses first so I wouldn't know which one I was listening to. And I could not hear a difference. I thought that maybe my inexpensive monitor speakers just couldn't reveal the difference. But there had to be one, right? I mean, a $500 software program vs. the creme de la creme of digital audio converters that costs more than my car?
So I decided to test my friend the next morning when both our ears were fresh and new. I did the same test. He closed his eyes. I switched back and forth between the two signals. The switching was so good and the two tracks of audio aligned so tightly that you could not hear when they were being switched (no click, no stutter, it was totally seamless). After about a minute of listening he asked, "Have you switched them yet?" I said, "Yes, I've been switching them this whole time." He said, "Oh... well tell me when you're switching." So I said, "A" when it was the first one and "B" when it was the second. I had him guess which was which and wrote down his guesses. His success rate was about 50%, just what you'd expect from a random double-blind A/B test. And he changed his mind throughout; "A is the Prism. No, B is the Prism. Yeah B. No A."
Remember, this is a guy with better trained ears (not better ears in general, mind you... better trained ears) than probably anyone here. And he could not hear a difference.
We were both surprised to say the least. Both of us expected the more expensive Prism to decimate the Cubase upsampling. Why would it not? And my friend was certain the night before, where we were not doing a blind test, that the Prism sounded better. He even pointed out areas in the audio that were 'better' that night. But that morning, with eyes closed and not knowing which was which, he could no longer hear any differences at all.
The point? Nobody has super ears. There are limits to our hearing, to all our senses, and our perceptions are constantly colored by what we think should happen, what we think the results should be, by what we already believe. The only way... the only way to arrive at an empirical truth is to remove those colors and biases from the equation. The only way to do that in audio is double-blind testing.
To say "I trust my ears" is to deny that your ears are untrustworthy. I think everyone has experienced seeing something out of the corner of their eye and you turn your head and nothing is there. Our eyes play tricks on us all the time. So do our ears. All of our senses do. Because our brain is the interpreter and it uses certain processes on the data it receives that many of us don't realize nor are we conscious of it. Our brain filters the information it is fed based on past experiences, preconceived notions, confirmation bias, ego, cognitive dissonance, and other inference systems (to use a phrase from Pascal Boyer). It's just the way we are.
I've posted this video before (if I remember correctly) and it's worth re-posting. It's long but it's worth watching the whole thing. They cover all the ways in which our ears fool us and there are some pretty funny anecdotes in there, including James Johnston (an expert in acoustics, psychoacoustics, and DSP) talking about how he did a double-blind test on fellow AES members with two amps; solid state and tube. Except that the tube amp wasn't actually working; it lit up but there was no sound. He wired up a false switch that he claimed switched between the two amps but really it did nothing except make a satisfying "click". It wasn't wired to anything. Not knowing this, most in attendance chose the "tube amp" as being better, even though they were listening to the same amp every time they flipped the switch.
Anyway, long post... sorry for that. But as abrasive as he can sometimes be, Scott is correct. And Kevin (who is anything but abrasive) is correct as well. This stuff is not subjective; it is objective. It's been tested over and over again. Certainly one can believe whatever one wants but at the end of the day, that's all it is; a belief.