I have a Laney DB 300C combo, with two 12' speakers. I am not very happy with the sound, the speakers start to distort too early and it doesn't handle low notes very well. Because of that, I'm thinking about getting new speakers. I have been looking at some Eminence speakers, and the Thiele-Small parameters says "Compliance Equivalent Volume (Vas) = 67,88 liters" (Delta 12LF). Does it mean that each speaker needs 67,88 liters of cabinet volume? The cabinet part of my amp is about 100 liters, is that 45 liters too small for the two Eminence speakers? Are there perhaps other 12's that will suit my combo better? Also; I've read about tuning a cabinet after the speakers. Do I have to do that if I change the speakers in my combo?