Audio

Microphones

In general terms, microphones fall into one of two categories; radio or cabled. Radio mics are available in two types, either tie clip ‘lavaliere’ or hand held, and are battery powered. An alternative term for either is ‘roving’ mic, but this is generally applied to hand-held only. Cabled mics can either be hand held or are smaller 'pencil’ types as used on lecterns. To varying degrees both of these are restrictive in their mobility, due to the fact that a cable is needed to plug the mic into. For the recording of boardroom meetings ‘boundary’ mics can be used. These too are cabled, and sit flat on top of a desk or boardroom table. The mics are then connected via a mixing desk into a recording device such as a mini disc player or hard disc recorder. Because of their high sensitivity (they are designed to pick up sound from any point in a room) they are not recommended for use with PA systems, due to likely feedback problems.

Playback devices

There are now many different types of machines used to play back audio such as music tracks. The standard CD player has now been supplemented by devices such as mini disc players, hard disc recorders/players, laptops and even iPods; although in practice these can only be used to play background music.

PA Systems

Fundamentally PA systems haven’t changed too much over recent years, although the clarity is much improved over previous generations of equipment. PA systems are made up of 3 basic elements; The mixing desk is the heart of any PA system. The sound technician will use it to take all audio inputs, be they mics, CD players etc, and using the controls will send any combination of appropriate mics or playback devices at any given time out to the amplifiers to be heard by the audience. The amplifiers job is simply to take the signal from the mixing desk and amplify it. Loudspeakers are the final link in the audio chain. They vary greatly in size and style, some are specifically designed for speech or music, others are designed as all-round units.