Here's my amp history...I had a Hartke stack ( 15 and 4x10) powered with a Peavey Megabass. Hated it! The weight, the tone, everything. The salesclerk showed me a SWR SuperRedhead. I plugged in, and without touching a dial, knew that was the sound I was looking for. Played a good 3 years with it, and absolutely happy with it. Then a joined a little louder band, she still kept up, but eventually the speakers blew. SWR rep said I should really invest in an extension speaker. While she was in the shop, I had to rent a Yorkville combo, and was quite pleased. So I bought a 1x15 to use with the Redhead. Again I was happy. Three weeks ago, my drummer filled in with a band, and their bass player had a HUGE sound. It was a monstrous Peavey cab. An 18 with two 10s They played outside, and he filled the air. I had two outdoor gigs the next week, and I just couldn't hear myself unless I was right in front of amp. Should I buy the SWR 18, a different (better?) 15...say Ampeg or Aguilar? Is there that big a difference between a 15 and an 18? (My drummer thinks so, but he's a drummer!) Or is the Redhead just not powerful enough, and I need a whole new setup? Maybe a preamp, power amp setup? The Redheads 400 into 4 ohms, 450 into 2 ohms. I play in a loud R&B band, with a 3 piece horn section, and a polka band as well.