I developed my test CD from songs that I was always hearing distortion when I increased the volume, which i tend to do for great songs.
A few that I use;
Genesis - Original Lamb version Carpet Crawlers. When Peter Gabriels voice gets low, and if the volume is up, it should sound clean and clear. Until about 8 years ago, I had never heard it loud without distortion, which caused me to turn it down. I can't stand distortion.
Sarah Brightman - Anytime, Anywhere! Phenomenal! Epic! Amazing! Especially with a little volume. I got to hear it loud properly for the first time about 8 years ago.
Sade - Love is Found - I saw her do this live at the Bell Centre in Montreal. It was unforgettable! The CD version is the same. Powerful, impactful, and will bring your system to its knees if there are any problems.
Avril Lavigne - Sk8tr Boi - If you haven't heard the almost subsonics on this song, either you have never played it, or your equipment isn't up to the task. It is the only song I have ever played that caused my Bose 1801 power amp to peg driving 901 series 2 speakers.