Plane and simple DONT BUY CHEAP CABLES now that is not saying you have to spend 150 on a 6 foot cable but 20 buck cables from super store or crappy tire just dont cut it. A good example is my sub cable i was running a middle of the road monster cable to it sounded OK but it was realy missing the Mid bass as it is a PSB sub sonic 7 with a 15 inch driver I went out a spent some money on a Good Monster cable made for a sub and man what a differance np more lack of mid base I had to turn down the volume on the sub. I probably have a $1000 in cable hanging behind my system. I use my wife as a test subject when I do any upgrades as she isn't swayed by the price of the cable As I dont dare tell her
So she dosent think it sounds better just because it cost more.
If you spend any time on any A/V sites or forums you will find this is a big on going topic and it will be going on for a long time