Quite possibly the venue is at fault here. I used to use a Sandberg Basic VM, with an LM2 through a Schroeder 1212. A marvellously punchy rig that always delivered, until one gig where, despite all the usual settings, it was inaudible to me. Tried shifting the eq around but without any success. Next gig, different venue, all back to normal, IIRC. Such are the vagaries of venue acoustics and bass frequencies it seems. Doesn’t stop it being a huge PITA.