Find the CD of Horowitz playing Rachmaninof's 3rd piano concerto with the New York Phil. The don't record like this anymore, but you will now how good your system is as you hear more details . . like the oboe player breathing or someone gossiping in the audience in the middle of the performance. The 3rd mov't has plenty of low end to test bass.

In general, ask me anything of a classical nature for music demo testing.