What do you use to check for brightness?

I'll post this in computer audio because that's what I'm dealing with, although it applies more broadly. Sometimes tonal brightness is obvious, even painful. But most of the time it's more subtle and too easy to get used to; i.e., where "I just know" might not be so reliable. Do you have any recordings, music files or online audio sites that you fall back on, where you know that if a system sounds like such and such, it says "bright?"
Most systems are plagued with high frequency problems of various types. Especially when the volume is turned up. We tend to accept a great deal of noise and distortion without too much complaint. Pretty easy to blame the recordings and just live with it.
One CD that comes to mind that has some high notes that can be overly piercing is Roger Waters Radio KAOS. I love the recording but some notes can make it easy to detect
a cable, equipment or speakers characteristics (spell check).
Thanks for those ideas. Developers and reviewers have certain tracks they use for testing equipment. After awhile, one can get overly used to one's own. I envy those with perfect pitch who don't need reference points.