1. Ill-defined expectations. The first and most important thing you can do is to define your expectations. Is the church's primary objective intelligibility? To arrive at that goal, are you willing to allow the loudspeakers to be visible? Is the system to be operated manually or run automatically? What about music and bandwidth? At what level must the system operate? The lower the frequency and higher the sound level, the greater the cost.
These and many other expectations must be clearly defined in writing. Then, have your document reviewed by a qualified independent person who can be sure the expectations can be met.
2. Bad acoustics. The acoustical environment into which the sound must project has a critical impact upon the sound heard by the listener. Churches must consider the relationship between the natural (physical) acoustics and the electroacoustics. The former has to do with the quality of sound while the latter affects the composition of the reproduced sound. A good sound system in a bad room will still sound bad, but a mediocre sound system in a good room can sound good.
3. Power problems. Improvements in sound system component quality have exposed long-existing problems in AC power in churches. The same "clean power" requirements that are appropriate for a computer or security system should be used for the sound system. Also, consider the long-range goals for performance. If there is a likelihood of performance sound (such as that used for special effects), extra power will be needed. During design, this power is cheap--as a retrofit, it can be cost prohibitive.
4. Underfunding. Not knowing what expectations really cost is another common mistake. Consider the following: Church members arrive with a mental image of the type of sound they expect to hear. Where is that image formed? For most, it begins at home with a music system they purchased for $500 to $4,000 or more. Their cars have systems that often cost $1,000 or more. In both cases, they are sitting a few feet from the speakers and have "perfect" control of the surrounding environment. Sitting in church, they are at a considerable greater distance from the speakers. Distance has a major impact on the sound being heard.
Using an average cost of $1,000 for a home system listened to by two people, we arrive at a cost-per-seat ratio of $500 per seat. In a 1,000-seat auditorium that same ratio would equate to a sound system costing $500,000. Sure, few systems actually cost this amount. However, the listeners are subjectively evaluating this church's system using $500-per-seat ears. Now you can see why the general conception, especially of the unchurched, is that church sound is always poor.
5. Poor operation. Churches can no longer ignore the fact that they need properly trained operators. This takes money--either to send lay operators to seminars so they can learn, or to hire professional operators.
6. Bad decision-making. It's important to involve qualified experts in your decision-making process. Having uninformed church committees make decisions on a very technical system is a set-up for trouble.
Procuring a sound system that is pleasing to listeners' ears is not an impossible dream. But it does have to be planned well in order for the result to be optimal.