What Eric said....OR.....take the opportunity to play differently. Sometimes I enjoy the "free pass" provided when the sound is not in my control or to my liking. It can be liberating to let it go and just enjoy the sound that I have instead of getting dark about the sound I wish I had. Sure, there are nights where it ain't too happening no matter what, but when I can find what my bass is willing and able to do in a given situation instead of trying to force it to do something that just ain't going to happen at the time, the music usually comes out better. For me at least, it usually works better than fighting it all night long.