| My process goes like this:
1. Split the bass into two tracks.
2. Leave one full range, and apply a low pass filter, or EQ out everything above 150hz (ballpark) on the other track. This leaves you with a full range track and a sub track.
3. Compress the sub track to the point that it has little to no dynamic range. You want it as steady as possible. For modern RnB stuff, I add a very slight amount of reverb to it as well.
4. Solo the kick, snare, lead vocals (no backups or harmonies) and the sub bass track. Mix these tracks relative to each other in a way that's pleasing to listen to and fits the style of your music.
5. Next you have to bring this relative mix up to the appropriate level. If you're mixing on a console/desk, the 0db point will typically have upwards of 22db of clean headroom left. If you're mixing on a DAW (software), 0db is typically where you run out of headroom. On a console/desk, mix the relative mix you've created up to 0db. On a DAW, mix the relative mix up to -12db. Depending on how much "stuff" goes in later, you may have to reduce these by a few db's to keep from running out of headroom.
6. Bring in all of the other tracks on top of this foundation, including the full range bass track. This part has a lot of other methodologies as well, but I won't go into them. With the foundation in place you can start building the sound a lot more easily. That should also satisfy you keyboard player's need for soft, pillowy bass and allow you to mix in bass with detail and character on top of it.
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FS: DBX 286A Channel Strip (FS thread coming soon!) | 
rather than the really muddy sammick I have been using. And I wholehartedly agree to the calls for MO BASS in the mix. 
