Just recently discovered using the volume knob differently on both the amp and the bass have helped my search for the sound.
Usually just kept the bass volume all the way up, and brought the volume of the amp up to taste. Ever since pickin up the SVT212AV, ive had to rethink and tweak the old V4B to get what i was after.
Finally found that i can run the amp almost wide open, or certainly much higher than i would normally, and bring the volume on the bass down. Its much easier to get the clean tone i was after, which isnt that clean really, and when you want the heavy grit, just bring up the volume on the bass. It doesnt get much louder really, just gnarly.
I scoop the low mids a bit (300k on the old V4B), boost the bass, treble stays flat, ultra hi/lo off, and the horn is off on the cab. Its slices, it dices, it grinds, it pounds, these are a few of my favorite things, all within the turn of a knob. No pedals needed. Pbass with 250k pots, orange drop cap, Lollar overwounds and TI Jazz rounds. So far the best rig and set up ive had to get whats in my head out of the amp.
Good Luck!!!