There are plenty of discs with wide ranging musical styles to use as demo material. Most of the audiophile oriented labels produce several to choose from. Find Telarc and Chesky on the web. SACD and DVD-A both have several demo discs for each format, the SACD will play on any CD player and the DVD-A will play on any DVD player, You will be listening at lower resolution than the SACD and DVD-A formats if you're not using a player designed for that format, but the discs are still recorded very well. Demo discs range from a particular selection of music recorded very well to a collection of pieces which showcase different aspects of your system. The car stereo folks have plenty of demo discs which emphasize bass or dynamics. Occasionally one of the audio manufacturers such as Sony, Pioneer, Denon or JVC will produce a test/demo disc to show off something their new products can do especially well.