Goals for an Optimal Sound System

Whatever the use of the room in which the sound system is installed, you naturally want everyone in the room to be able to hear -- well -- naturally! This means that the system should reproduce sound accurately, cover the room evenly, and not add extra echoes or reverberation.

The main purpose of the system is to make sound louder. How much louder a given system can make the sound is limited by the gain before feedback. Feedback is the squeal that results when too much sound from the loudspeakers gets into the microphones and is amplified again and again. Many people are surprised to find out that the maximum gain before feedback can be predicted mathematically. The equation includes the following factors:

• the "liveness" or reverberancy of the room
• the distance from the talker/singer to the microphone
• the number of microphones in use at the same time ("open mics")
• the distance from the microphones to the loudspeakers
• the directional characteristics of the microphones and loudspeakers

Live rooms, large distances between microphones and talkers/singers, and additional open mics reduce the maximum gain, making feedback more likely. When microphones are close to the loudspeakers, especially if the mic and loudspeaker are pointed at each other, feedback problems are increased. Basically, anything that keeps the loudspeaker sound out of the microphones will help.

Finally, the system should be easy to use, and should not include extra "bells and whistles" that you don't need, and which the system operators may not understand. A common example of oversold systems involve small-to-medium churches with traditional worship styles in which overzealous companies have installed systems that would suit a large church using a live electric band. These extras are often promoted as adding extra capabilities, but if you don't need those capabilities, they really just add cost, confusion, and possibly increased maintenance problems.

Next: The Effects of the Room