In both PA and any other audio application (home, studio, live, etc.), sound goes through three phases: capture and conversion into an electrical signal, signal processing and amplification, and conversion back into acoustic pressure through the speakers.

A detailed study of all the elements that make up the sound chain requires reviewing two important concepts: frequency response, which affects all components in the chain, and directionality, a characteristic of microphones and speakers as transducers of electroacoustic energy.

