Ethernet Cables, do they make a difference?

The Oxford Dictionaries Online defines the scientific method as "a method or procedure that has characterized natural sciencesince the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses".[1]

OK,
Last evening I performed a listening test with a non-audiophile friend of mine to learn if he perceived a difference between a CAT5e and my CAT7 cable. The test was lame and am sure not up to the standards of most on this forum, but I'll let it be up to you to decide.

Streaming Source - TIDAL Hi/FI/Master
Gateway - Arris
CAT5e and CAT7 10' runs directly connected to Arris Gateway
Music - Keith Urban, Graffiti U, Track 7 (TIDAL MASTER)
PC - Built myself Gaming rig
Service - Xfinity 175mbps copper coax to home
Audio System - Krell and Sonus Faber

I repeated the test below three times, and all three times he selected the CAT7 cable. The way I performed the test is I told him there were two different Ethernet cables I was trying and wanted his opinion if one sounded better to him, I called them cable 1 and cable 2, Cable 1 being the CAT5e and cable 2 the CAT7.

I played the entire track with each cable starting with cable 1 and I told him it was cable 1, I asked him to keep his opinion to himself until we repeated the test 3 times, telling him each time I repeated the track what cable I had in the system, either 1 or 2.

Results:
My friend preferred cable 2, the CAT7 consistently. I asked him how substantial the difference was and he said without reservation that he could hear a difference, and that difference was the CAT7 cable sounded "smoother". Now though my friend is not an "Audiophile", I agree with his assessment. So, in the end, either I have a system problem, or, just maybe, there is a difference in Ethernet cables for reasons I can not explain.

Thanks for reading and please do not bash my non-scientific cable test, it was the best one evening, one person test I could pull-off.

Good test! 

@grm. Good test. You may want to try a Cardas, AudioQuest or Wireworld Ethernet cable. They run around $200. If the one you buy fails the test, sell it here on Audiogon. 

@grm Thanks for posting your results. The test isn't lame. It is realistic. Could it be published in a respected scientific journal? Nope. Does that really matter? Not at all. Will others criticize it? Undoubtedly. But, the critics may have biases that will not allow them to ever admit hearing a difference that they zealously contend is empirically impossible to hear.