I remember reading somewhere on the Interwebs (so it must be true....) that it is a bad idea to run bass through a guitar cab because of how far the cones flex for bass. But here's my situation... I'm working on a Motorhead tribute. The bass player is using my '71 Super Bass head. He's been bringing a bass cabinet that he's borrowing from the bass player from his other band (he's a guitar player in the other band...), but the thing is a beast to move and it's not always easy for him to get his hands on the cab on the days the Motorhead band practices. I've got a spare Marshall 4x12 loaded with G12T-75s I could let him use, but I don't want to blow the speakers. We run the Marshall with the bass mostly rolled off, which is what hear Lemmy does. We play reasonably loud (hey, it's Motorhead after all), but the PPIMV on the Marshall isn't cranked up anywhere near max. So what say you, TGP? Should I let him use it or not?