Phew.
You need to read up on cables and from the sound of it, a few other things. I'll tell ya, anyone who is using Bose speakers and looks for improvements via cables is going about it pretty backward. Speakers first. It's almost always in the speakers. Forget about cable and break in myths and focus on the things that really make a difference.
Audio interconnects and speaker cables myths and facts are revealed in this informative interview. What makes a good AV cable, and the real science behind them is discussed here.
www.audioholics.com
That said I believe you perceived a difference due to some expectation bias. I'll bet you a dollar you wouldn't have detected anything if you set it up DBT style, where you don't know which is which. Here's kind of a fun read.
There's no point arguing with condescending people who believe that they are just right and everyone else is just wrong no matter what you can prove. :D You might tell him, "Man, your system rocks, but your bass kind of sucks. I highly recommend to add at least one subwoofer or even two. They...
forums.audioholics.com
We coached someone on how to perform a DBT for his friend who swears he can easily tell the difference.