OVer here in germany, Mic'ing the bass is somewhat exotic.
Sad but true. Normally, the bass gets DI'ed before the signal hits the amp.
So, i've played lots of gigs with my sound on stage and the sound the PA guy thought cool in the hall.
Over the years i've discovered a few possibilities for that problem.
first and foremost, it can help greatly to talk to the soundguy before he rigs the stage with his stuff. And when doing so, never demand anything, but ask nicely wether that can be arranged or not. I know these guys have to deal with a lot of idiots on the four strings that want their crappy EQ settings that work for their broken amp in their rehearsal room where everything is set up wrong translated to the stage, resulting in
disaster.
Never get on the stage when all the setup's done and cry for a mic instead of that crappy DI.
Second, provide a solid, working solution all by your own. bring your own mic and/or DI.
Last time i tried to have my amp's DI (post EQ) used for the signal instead of the DI before the amp, the guy told me that if we do it that way, he'll try and make the PA sound like my amp does and i'll have to live with the consequences. I told him we'd give it a shot and if he thinks it's not working, we'll do it his way. Turned out great.