A guy I know at my church has a corvette and a really nice audio system. One day, he wanted me listen to his speakers and give hm some feedback. He put in a CD-RW with what he called "bass-testers". I guess it was just music, but all you heard was super deep bass. No singing, guitar, drums. Just bass. It's used just to see how good your bass is. I don't know if "bass-testers" is the official name of it. Have any ideas?