Depends what you are trying to accomplish. Sure, orchestral works are good to hear full range sound. But to assess the blending of your sub with the rest of your 5a's, I'd recommend that you get a decent recording of a string bass and listen as the bassist moves up and down the scale. My favorite for this is Ray Brown or the Ray Brown Trio. I've used Ray Brown's recordings to set up my Vandersteen 2wq subwoofers with my martin logan CLS IIz's mains. Good luck.
harry
harry