Alright, so I found 2x 150 2x 10-12" (dunno forsure) speakers (2 rectangle shaped boxes, with 2 speakers in each...dunno the propper word for the box :P)

iF I hook them up to a power mixer I should get a 150 wat power mixer...correct?

will this be loud enough to be able to hear the vocals over the drums, guitar, and bass?

also, how much do 150 watt power mixers go for (used or new)