Saw Cannibal Corpse recently, got one of the best bassists in extreme metal and he was literally inaudible. Top flight gear - Spector bass, Radial Tonebone and Darkglass B7K on his pedal board, into an Aguilar DB750 and DB 8x10, when he played a couple of notes between songs it sounded great, however I was watching his hands, stood next to the sound desk and couldn't hear a single note. They had their tour manager on the sound desk, so no real argument about not knowing their sound.