Jay-J is one of the most prolific and respected producers and engineers in Dance music this decade.  Here's his tip concerning utilizing wide stereo bass sounds but keeping the low end fat.

Many synths (and virtual Instruments) utilize stereo effects, such as chorus or stereo delays and reverbs, to create really wide stereo sounds or patches. These patches sound great when you are auditioning them but not realistic, in my opinion, when it comes time to mix. To create bass sounds with a wide, spread out sound while retaining a tight solid bottom end I do this trick:  

First Up

Split to 2 sets of tracks by duplicating the main bass track. I print my virtual instruments to audio tracks so in this case its 2 stereo audio tracks but this techniques could work equally well with instrument tracks.

Secondly

For one of the tracks I put the pan to center on both sides and leave the other hard panned left and right.  In Pro Tools there are two pan knobs on a stereo track.   One for the left channel and one for the right so in other programs this might be different. (He's using ProTools here, but in the case of Logic/Cubase etc you could acheive the same effect by just adding a third copy of  the Bass track, panning one hard-left, one hard-right, and one to centre)

Finally

I use a filter on both tracks.  The mono one is for the lowest frequencies so I put a low pass filter on that track with a cutoff at about 130-150Hz and on the other track where I want the wide sound I use a high pass filter and set cutoff frequency at about 170Hz or so.  Both are usually a 24db filter. (Again, you  could use this method in Logic, putting the high pass filter on the hard-left/hard-right tracks and the low-pass on your centre-panned copy.)

This gives me one channel that is mono and contains all the lowest frequencies.  I compress that mono track pretty hard so any little volume changes resulting from the stereo effect from the patch will be minimized leaving a saturated, tight, and contained bottom end.  Then I mix in the stereo track to create the width and depth needed

This same approach can also be done with 2 different bass sounds, one for the bottom frequencies and one for the higher, wider, stereo width.  

Check out Jay-J's outstanding Loopmasters Artist Series Pack here