Hey guys i bought with the intent of moving up to bi-amp, and still havent done so. Right now i got the hartke 7000 (350+350) and a 4x10 workingman swr. I really feel like im pushing the limits of the cab, but im in a very heavy band and i have to complete with two bassy as all hell guitars both running line six's. I've actually had to change my sound from very bassy to a more trebbly sound that cuts through the bassy guitars. Anyways back to the original question, the amp head i got was designed for more than one cab.. i actually think its able to do 4, but i was considering going for a 1x18 to reclaim the lows. Would this really have much difference from a 1x15? and over all if i did get one of these would it really make a difference?