Just that. Moreover, I've been playing more with MSO, experimenting with different combinations of filters, all-pass on one sub or the other vs no all-pass, etc. Using different EQing schemes in MSO gives different delays. And they don't deliver the same delays as REW using the alignment tool. The REW result does come closer to the delay calculation by measured distance, FWIW. Does this make any sense at all? It seems like something is fishy, or perhaps I'm doing something wrong. I'm assuming that the delay filter should be on the sub closest to the MLP. Any ideas? Thanks and cheers,