Introduction2 - Fighting the Laws
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
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.
to Introduction 1