PA (public address) systems utilise microphones, loudspeakers and other related equipment to enhance audio coverage in commercial premises and public venues. Buildings and venues with large spaces or lots of rooms will require loudspeakers widely distributed to cover these areas so that uses such as safety announcements, advertising or music can reach the occupants. Typical applications include office blocks, bars, shopping centres and stores, lecture theatres, schools, places of worship. Multiple microphones and other sound sources can be integrated to maximise usage and every system is scalable ensuring that wider distribution is possible.