So do you need music to test the speed of your drivers?

Try this:  Charly Antolini, "Knockout 2000."  Strong drum and bass of real instruments.  All instrumental.  

Not my cup of tea for pleasure listening but it's well recorded and tests the low end without resorting to hearing pipe organ. 
I've heard people talk about speed but I don't know what they're talking about but would like to understand it.
Hi n80

Good question.  I would say speed means can your drivers keep up with fast, heavy percussive/rhythm passages?  The amp is arguably tested here too. Do the loudspeakers keep pace or do they fall apart?  Do they break a sweat, so to speak?  Or do the speakers seem to be ahead of everything and enjoying being intensely driven?
Classical music with orchestral crescendo(s) are fast in nature and will give any speaker a live workout.  Thank You for the tip on "Knockout 2000".
Happy Listening!