Used to drive passive speakers, the external power amplifier was once common place in any decent size PA system, both in the garage for band practice and at the side of stage powering huge speaker stacks at festivals. The recent developments in the technology of power amps has lead to the ability for modules some enough that can be mounted inside the speaker box itself without comprising sound quality, volume and headroom all that much. Though there are still often compromises taken by manufacturers of powered speaker to lower costs and power amplifiers still have their advantages in delivering a cleaner sound at high power levels over greater periods with a much lower risk of peaking and overheating problems.