I learned somewhere that to provide maximum entertainment potential, musical performances need to include "events." Events are things that punctuate the music, break the pattern, draw attention, etc. One or two of these per hour set is about right.
An example of a set event could be bringing 2 or 3 people up on stage to dance with the band. Or, a common one is the old "break it down" trick where you cut everything out but the rhythm section and then build back up to a climax with audience participation along the way. Think about the middle section of the Isley Brothers "Shout" and what bands usually do with that.
If you aren't in a band where the bass player is the bandleader or where bass solos are a natural part of the music (like a jazz combo), a bass solo makes a good musical event too. But you have to do it right.
If nothing changes in the music except the bass player takes a solo instead of playing the bassline, it's going to suck because two bad things happen at the same time:
- The bottom falls out of the music
- A guy tries to take a solo and nobody can hear him because the solo register of his instrument (the bass) competes unfavorably with too much else that's going on.
So it actually makes musical sense in most cases to start a bass solo by removing all other instruments except the drums. This announces to the audience that something special is about to happen. Maybe the keyboards or some very light guitar comping remain, depending on how well the rest of the band can follow the form without the bass part, and on how "out there" the bass solo is.
Certain types of bass solos follow the roots pretty closely and untrained ears can still follow the form hearing just the bass solo. Other bass players solo just like Trane and unless their keyboardist is Chick Corea, he's probably going to lose the form and then everyone will be screwed, including the audience. All the members of your band have to be able to work with you productively and cooperatively during your solo for it to be effective.
Then, if the bass player is a good soloist, he or she can construct a solo that builds tension and approaches a climax all on its own, with no real help from the band. That's super awesome to watch, but you don't see it often unless you paid for a ticket that has the bass player's name on it. In any other case, it helps for the band to gradually layer in more voices and chordal activity so that they can help the bass player approach the climax of the solo and for everyone to be able to follow along - to the point where at the very end of the solo you've gone from nearly no accompanying activity to everyone playing behind the bass player, and playing loudly. You just have to get there the right way.
In these ways you can make your bass solo into a musical "event" that helps give structure to your set and keeps your audience involved.
This makes me want to play a gig.