Great question. AS I read the manual specs it will serve 100 watts into the internal 8-ohm speaker. Add another 8-ohm speaker (total 4 ohm) and you will get the full 200 watts.This is possibly a stupid question, but please bear with me. I am considering one of the new Rocket Bass amps. If I understand correctly, the RB-115 is 200 watts with an external speaker at 4 ohms. But, the internal speaker is 8 ohms and the amp is only 100 watts with an external speaker at 8 ohms. Does that mean that without an external speaker the amp will only be 50 watts and, therefore, quieter than the RB-112?
re. volume: I think it's safe to say that the 1-15 would be the better amp for full band/performance volume.