The practices of Christian worship have changed over the years to bring the celebration of the mass closer to the congregation. Once, the priest or celebrant would conduct the service from the far end of the chancel, tens of meters away from the congregation in the nave of the church. Now it is common to conduct the celebration from an altar positioned at the level of the transept, much closer to the congregation in the nave.
If you understand some of the terms in the above paragraph, then you might be in a good position to provide sound engineering or installation services to churches. And believe me, many are in dire need. If you are not Christian, or not religious at all, that probably won't matter as long as you work for the good of the church (and don't charge them too much!). I'm a non-practising Christian yet many of my best recordings have been made in synagogues; being 'of the faith' is often less important than being able to do the job well.
The problem in a church is that the intelligibility of speech is vitally important. The way to achieve this is through many small loudspeakers placed close to members of the congregation. Ideally, no member of the congregation should be more than three or four meters from a loudspeaker. This arrangement makes the direct sound louder than the general reverberation in the building, and therefore more clear.
However, music doesn't sound so good played through small speakers. So a conventional PA system would be beneficial for the musical aspects of the worship. The ideal would be to have a center cluster of loudspeakers, such as is used for a theater musical where intelligibility is also important. The cluster would be mounted a few meters further forward than the front rows of the congregation, high up to get a clear line of view to all corners of the building. In a center cluster, each full-range loudspeaker covers its own area of the audience or congregation. Some places in the seating will fall on the dividing line between two loudspeakers, but the general rule is that you should be able to look up and see one speaker pointing towards you.
The center cluster will not give quite as good intelligibility as the distributed speakers, but it should be perfectly good for music.
The problem might remain that the church elders might not want to see the loudspeakers. But worship has changed through the ages to fit the needs of the times. The message doesn't change, and there is no harm in getting it across as well as humanly possible.
Just like the architecture of worship, the installation of a wonderful sound system could be considered an act of praise in its own right.Come on the FREE COURSE TOUR