Saw Karnivool in southampton last night! and i can say was that i've never heard such a good bass tone at a small gig!
This popped up on talkbass at some point and might help you out, this is from jonto a member on there:
"I use an Ashdown EVO II 500 live and in the studio I'll use a number of heads, mainly an Ampeg SVT-CL or SVT-2, plus also Eden, Sunn and Aguilar gear, as well as my Ashdown of course. I use a boss bass equaliser (GEB-7) to reduce a bit of the low mids (160Hz) that are naturally produced from my Warwick Thumb-6, I also run an ODB-3 but I've just bought a Tech-21 XXL, which is a monster distortion, a bit differnt to the ODB-3, which is an overdrive. I also use a DD-20 boss delay and an OC-3 boss octave pedal for some parts of newer songs"