Keyboard amp or not I would say is not the issue. If you sing and have a drum machine, you are still using a frequency range that needs a decent PA. I would also say that advising people to ignore a forum is rather ignorant. Ok, I apologize if I hurt someones feeling with my Barbetta comment, I just mentioned a discussion in a forum of a competitors forum, forget I mentioned it! The general concencus is that 15" speakers are far from ideal for vocals. The gap from 15" to 1,25" horn and tweeter can be rather big, meaning that as you turn the volume up, you start to lose mids because the prime frequencies for a tweeter and a 15" horn start taking up the increase in power. Therefore a 12" is better suited, less gap, less clipping and loss of mids where the vocal and lot of percussion and the guitar frequencies lay.