Live sound reproduction system has two main forms:-
A "sound reinforcement" system enhances the volume of the initial sound and will be designed so that as much as possible the listerner will not relaise that an artifical system is being used to make it easier for them to hear the initial sound.
A "PA" (an acronym of "Public Address") is a usually simpler design that just amplifys the initial sound and it will be obvious to the user that it is being used.