I have heard a few things about SWR cabs not being able to handle Low B very well, particularly the Son of a Bertha cab and Goliath cabs. I think I read somewhere that they are made ideally for E range and up. I use a working man's 1x15 and havent really had problems with it. However, at my last gig I heard some farting out around midway through the show (for some reason my gain goes way up once something in my rig warms up, maybe the tube in the ART levelar I am using), but this might have been my other cab in the setup. Anyone have experience with this B issue and SWR cabs?