I can't speak to the bass, but my keyboards all sound better when someone else is playing them and I am sitting out in front of the keyboards/amps. The first time this occurred to me I was shocked at the difference. Not that they sound bad when I am playing, but so much better when I am front and center of the amps. This is not relative to player skill. Some are better, some not.
Normally, when I am playing, I am behind or aside and behind my amp. I assumed that to be the cause of the difference.