I have been trying to replicate the RATM bass tone for @TheIndieKid and I've got something that sounds vaguely similar, except that the EQ balance is off somewhat, however, trying to add more bass or lower the treble results in a room shakey boom, which is annoying. I made the patch on the MS60b but it's transferable to the B3 - I'll type up the settings I used in a bit, and would appreciate if anyone could help adjust it to sound accurate, I think it's close, I found that, at least on the songs (and covers of) that I used as reference, that he uses a very warm tone, with an OD/Distortion with a very low gain, at least, to my hearing it sounds like that, I'm not sure if I should add a comp or something, but as the B3 only has three slots, it's hard to do that. If I was douing it for myself, I would utilise the combo of the B3 and the MS to have 7 slots to play with, so I could try different amps, EQ, parametric EQ, comp, distortion etc and fine tune it (plus then search for his wah and other effects to chain ) but with just the B3 (or using the MS60b as though it were a B3) I don't have the luxury.
So, I don't have my own patch handy, but I had previously asked about getting a RATM bass tone, and someone recommended using a mid-scooped Sans-Amp Bass Drive tone (modelled by the "Bass Drive") which I run into either a SVT or GK amp sim. If I recall, I use one of the compressor models for the third (actually first) effect.
John