Entering into the live sound realm for a bit - do you know the difference between a PA and a distributed power system? You've probably heard of a PA (public address) system system before. These are what live bands use, as well as even coordinators, etc. It's usually heavy box (mixer and amplifier combined) with lots of holes and knobs on it, along with two heavy speakers. You plug a microphone or two into the "input" holes, and two cables into the "output" holes on the heavy box. Finally you plug the other end of each cable into a speaker. You plug the power cable on the box into a wall, flip the "on" switch on the big box, and presto! You're ready to talk or sing into a microphone and have it be heard by everyone in the room.
PA systems are usually sort of self-contained, the speakers and amplifier going together as set. So the electronics are well suited for each of the components. Plus you only have (usually) 2 speakers on one system.
A distributed power system is what is commonly used in super markets, hotels, office intercoms, etc. The main difference between a PA and a distributed power system is that the latter has special electronics built in to the speakers, like transformers, and special amplifiers are used to power the speakers properly. The speakers’ onboard electronics distribute the power from the amplifier evenly and safely. That allows several speakers to be chained together with a minimum of worry that any of them will "blow."
Click here for the full article on distributed power systems from B&H.