When I do a sound/Eq check for a P.A. (typically for performing bands), my recommendation would be TOTO's 2004 CD "Mindfields".
Not only is it a superb album (for lack of a better term), it is exquisitely engineered. The whole audio spectrum is utilized; and, for me, it really helps to get the range of the snare drum just right.
If you're trying to achieve a nice, even response for your performing musicians, this is the ticket.
I wouldn't say all this if I didn't have the agreement of other sound techs.