Oh geez... I just dialed in the Empress Bass Compressor through the BassRig15 cabsim to sound exactly like my preferred setting of the BassRig15, but with just a little more punch. edit: and a bit more sustain.
Try this at home if any of your have these two pedals:
BassRig15 - blend at max, treble at 10 o'clock, turn drive up until just before notes high on the fretboard go from saturation to break up, then turn the bass up until just before notes played low of the fretboard start to break up, then reassess both.
Empress Comp will be harder to dial in for one's particular bass because look at all those knobs... But for me and a mustang with flats, input 2 o'clock, output up to unity gain, attack dimed, release noon, mix full on, sidechain 10 o'clock, 4:1 compression and colour set to scooped.
I have to admit right now I am in love with the tone of the Empress comp into the Bassrig15 cab sim... it's not very authentic, but man is it good.
edit: revision - i have the comp set a little higher than unity gain, as is the BassRig15, and the Comp needs to be played a little closer to the neck to round it out fully.