Should we have a center mounted speaker cluster for our room or a side mounted speaker system?
This is a very sensitive issue and there are many "die hard supporters" for both the center mount cluster and side mounted system with some good theories to support it. This makes for a controversial situation. In our experience, we have installed about 350 sound systems in churches and have put central clusters in less than 5 of them.
When to Use Ceiling Speaker Clusters:
In a very large church with a very high ceiling there are two advantages to a ceiling mounted speaker system. A properly designed system will give a more even sound distribution throughout the room and the ratio of distance from the front seats and back seats to the speakers is fairly small. This means that the volume is quite constant throughout the room. In a church with a ceiling height over 30 feet and a seating capacity over 800 this should be considered. In a smaller church however, these advantages are lost and there are many disadvantages.
The ceiling mounted speakers reduce your gain before feedback by about 3db, this means that you can get twice the volume from side mounted speakers before feedback. With the pulpit located under the ceiling speakers, the feedback can be even worse. Furthermore, no matter where you sit in the room, you will always hear the sound from way above your head with a ceiling mount, but the people speaking and singing are directly in front of you. I find this distracting. With side mounted speakers (about 8 feet above the floor) in most of the room, the apparent sound is directly in front of you at the proper height.
Stereo Speaker System:
You can have a stereo sound system with side mounted speakers. This is an advantage if you sing with sound tracks. You can't have stereo sound with ceiling mounted speakers. Also, installation and future service costs are reduced with side mounted speakers because no special lifts are required to mount them.
I'm not saying that a central cluster is always a bad idea, but it is an old idea which is giving way to the side mount. Most modern theaters have side mounted speakers now instead of central clusters.