I am having quite a time deciding how to spend my hard earned money on a new amp. I have researched a few medium priced amps and come down to a couple of options. The Carvin RC210 (2x10 combo, 600 watts, bi-amp) or a Carvin 600watt (or mackie M-800 I like the features better, but costs more) power amp with the 4x10 cab. I like the 2x10 combo for portability and features. But, I want to know about loudness, I have a 1x15 cab with a 100 watt PA head with Bass Pod preamp.