I've posted a few questions before about getting more volume from my relatively small combo amps (and I appreciate everyone's responses). I'll ask one more question and that'll be it . . . I think. My combo amp is GK MB150S 112, rated at 100 watts for the internal speaker, 150 watts with an extension cabinet. The internal speaker is 12". I don't have an extension cabinet for it. If I want to add an extension cabinet for loudness in a big band, brassy situation, here's what I'm looking at: GK's own MB 112 extension cab, an 8-ohm, 150-watt-rated 12" cab made specifically for my combo amp; or a Hartke 2x10 cab, also rated at 150 watts, 8 ohms. Any thoughts on which would give me more of a volume boost? Based on the "moving more air" theory, I'd think the 2x10 cab would give me more boost in volume, but on the other hand, if it's the same amount of wattage, just divided among more speakers, maybe it wouldn't. Any advice? Thanks in advance, as always.