The soundtrack to the movie American Beauty has some extremely low passages. And it's pretty good music, to boot. But for breaking in speakers, I'd go with a dedicated break-in CD such as the one Stereophile makes (I think it's test CD 3).
Software to give woofers a work-out
I just acquired a new pair of speakers with side firing woofers. I mostly listem to small jazz ensembles & vocals & I don't play loud. The woofer cones don't even move. At this rate, they'll never be broken in. Can you recommend some CDs/LPs with a lot of slam in the low notes ? Thanks.