Introduction2 - Fighting the Laws of Physics!

In the cases of reinforcement and amplification, the user is involved in a battle with the laws of physics. The problem is simple - take a person speaking quietly, place a microphone in front of him or her, and amplify the signal from the microphone before sending it to a loudspeaker. Essentially the same sound comes from the speaker - only louder!

So where is the problem? This louder sound, as well as falling on the ears of the listeners (the desired effect!) will inevitably also fall on the microphone which is part of the system. If it is loud enough at the microphone, it will be re-amplified and come out of the speakers again, and fall on the microphone again...ad infinitum! This increasingly louder sound quickly turn into a howl or squeal - the infamous "feedback"!.

Some Aims

The aim of the system designer, or operator, is to achieve the desired objective (louder sound) without creating feedback. Secondary, although almost equally important aims, are to create this louder sound without introducing unwanted sounds, such as hum or buzz, and producing as natural a sound as possible - no-one wants to hear a sermon which sounds as though it is coming down a crackly telephone line! These aims are achieved by selecting appropriate equipment for the job, installing it correctly, and ensuring that users know how to use it properly!.

Learn the language

Mechanics, computer engineers, doctors - just about every trade or profession has a language of its own, and P.A. is no different. In order to help you "speak the language" site sections give a description of the various components of a P.A. system, with notes regarding some of the variations found within any one class of equipment.

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