[LAU] Testing sync with 2 sound cards

I was recently fortunate enough to pick up a second Delta 1010 for my studio. I know that it's important to run these in such a way that one card's clock is slaved to the other. What's the best way to ensure that the cards are actually in sync? I've recorded an hour of a metronome in Ardour with the signal split to an input on each card and saw no drift between the tracks. I then played them back and heard no drift even after 30 minutes, but I have a feeling that this isn't necessarily a valid way of testing. Thanks! -- ====================================================================== Joe Hartley - UNIX/network Consultant - jh(a)brainiac.com Without deviation from the norm, "progress" is not possible. - FZappa