Audio Coverage

http://www.prosoundweb.com/article/the_big_5_how_to_illuminate_the_audience_with_beautiful_consistent_audio_co/P1/




1. Provide even sound coverage of all audience.
2. Provide adequate loudness before distortion.
3. Provide adequate loudness before acoustic feedback.
4. Be easy to understand.
5. Reproduce musical sources with adequate clarity and fidelity.

These are the “Big 5” rules of sound as outlined by Pat Brown. At first glance it may not seem so impossible to follow these rules, but when one begins to see that all 5 of these rules must be followed simultaneously it begins to seem not quite as easy. There are plenty of rooms that meet the requirements of two or three of these rules at a time, but it can sometimes be hard to find a room that will meet all five.
I know for me personally, many of the rooms I grew up playing music in and mixing in at my church barely met these rules. The rooms very rarely were actually built for music and the couple of rooms that were built with music and speech in mind were very spotty in terms sound coverage.

In the article comparisons were drawn between a lighting designer and a sound system designer. Similar to the ways that a lighting designer has to make sure that his light covers the stage evenly and completely, it is the job of a sound designer to make sure that his speaker choice at the distance they are away from the audience project sound evenly and completely. Brown translates this to terms of directivity, defining directivity as, the two variables that determine coverage: distance and coverage angle.

According to Brown, the larger a speaker is the more directivity it will have.
So if a speaker is to be far away from an audience it must be large enough to cover that audience with sound, however the closer a speaker is to an audience the smaller it can be to provide the same amount of coverage. This is not always an option as sometimes the person for whom you are designing a sound system might have strict requirements on where speakers can be placed. If this is the case it is important that one knows their room and takes the time to listen to the speakers in the room to determine if coverage is good or not. The problem comes when someone wants a small loudspeaker far away from the audience. It would be very hard for a sound designer to follow the “Big 5” with these kinds of restraints put on him.

Brown suggests that in order to ensure the best coverage one should hire a sound specialist that is equipped with the tools needed to measure sound coverage so as to get the best sound out of their system as possible. He suggests that one do it this way since the tools needed to measure sound coverage are often very expensive to acquire and it would be more cost effective to just hire someone to do the job.