Sound Systems 101

Our purpose here, is to provide some basic information, to assist customers in choosing and evaluating, equipment and systems. It is staggering really, how many systems are in existence (and used regularly), that suffer from the most basic flaws in design. Simple systems are not "Rocket Science", a little common sense and Junior High Physics go a long way toward eliminating the most basic problems. Of course, volumes have been written about equipment and system design, our intent is to "scratch on the surface",  just a bit.

Things to consider -

Is the system predominantly for voice, for music, or for both?

Voice only systems require limited frequency response, that is, they have no need for (and may even suffer from), low bass or high treble energy (sound). Telephones for example, have extremely limited frequency response, but they have no problem conveying voice conversations. If a system is for music (at least if quality is an issue), it requires considerably more range. Music can certainly be reproduced by a voice system, but it takes on a "thin, weak or canned" quality, no matter how loud it is played. A system designed for music, will generally reproduce voice with a natural quality, however noise (buzz, hum and hiss) can sneak in more easily, as the noise is often "in" the low or high ends of the sound spectrum.

Voice systems are generally much more sensitive to a highly reverberant environment (Church Sanctuaries, Convention Rooms etc.). The reverberant energy "smears" the consonant sounds in speech, making it difficult to understand.  Careful (professional) design and loudspeaker selection / location are the keys to a functional voice system, in a reverberant space. If you think professional design assistance is expensive, try installing a system in a highly reverberant space with no professional help - countless thousands $$$ have been wasted in this vain effort.

Is the system for reinforcement, for reproduction, or for both?

This is, for the most part, a way of asking if there are any microphones in the environment that will cause the system to "feedback" (howl or squeal). Feedback is often the limiting factor, in the amount of gain (and therefore volume) a reinforcement system will tolerate.

A system to reproduce recorded sound, typically does not suffer from feedback at all. A system with many open microphones, can be a "street fight" for every bit (or db) of gain / volume. If the system does double duty (reinforcement and reproduction), the designer may well be required, to make compromises that favor the more critical function.

Loudspeaker Type And Location (please repeat with authority, once again) Loudspeaker Type And Location

Many factors come into play in the systems design, none are more important (few are anywhere close) than Loudspeaker Type And Location. Many location options exist, but most are variations or combinations of the following  -

A central speaker (or cluster of speakers) location - This is often the best choice for voice systems, where the person speaking is visible to the listener. The "directional information" is kept intact, maintaining a natural experience for the listener. For this type of system, loudspeakers mounted (flown, in the business) high are usually desirable.

Two speaker locations (or split cluster) left and right - This is a good set-up for stereo music, provided the listeners are located in the center, relative to the speakers. Often however, most of the audience is much closer to one speaker location then the other, in this case the "stereo advantage" is lost, and the listener hears predominately one channel of the stereo sound source. These "split systems" are often  "run in mono", this is simply the best compromise for everyone in the audience, even for music. The high (flown) loudspeaker location, once again is desirable more often than not, with a split system.

Distributed systems - This system consists of multiple loudspeakers, usually located as near as possible, the listeners. This arrangement is used when the previous options just are not viable (separate rooms, or locations for example), or in highly reverberant, feedback prone, or just very large spaces.  Distributed systems may contain only a few speakers or dozens. A voice system at a race trace, or large retail store are examples of  typical distributed systems.

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