Room Acoustics - A Major Problem
One of the major problems we face in Church sound today is echo-o-o-o-o-o. Although a highly reverberant room can make a choir or organ sound great, it is at the cost of lost intelligibility. Sure the choir SOUNDS good, but can you make out the words?
Intelligibility refers to the ability for a person to understand the words being spoken or sung. It has nothing to do with how loud the sound is. You may have no problem hearing the voice, but if the intelligibility is poor, you can't understand the words.
What causes Room Echo?
Excessive room echo is caused primarily by two things - hard surfaces and high ceilings. The worst materials are glass, marble and concrete block. Next to this is drywall. The more hard surfaces you have, the worse the echo will be. For example an entirely drywall room is much worse than one with drywall walls and an acoustic tile ceiling.
The problem with a hard surface room is that there is nothing to stop the echo. The sound simply bounces from the back wall, to the front, to the ceiling, to the floor, back to the walls, floor, ceiling and so on. The decay time can be several seconds which absolutely destroys intelligibility. The solution of course is to reduce the amount of hard surface area.
How do we avoid and fix room echo problems?
To reduce echo it is best to "soften" some of the surfaces. A ceiling made with acoustic tile is a big help, not only for reducing echo, but also for wiring access. Heavy drapes and wall hangings are also good. A carpeted floor is a bit better than a tile or wood floor.
If you are planning an entirely drywall room there are a couple of things you should consider. Use large wood beams up the walls and across the ceiling. Not only does this trap the sound, reducing echo, but it also looks nicer. Also don't make the ceiling too high. A low ceiling reduces the echo delay time which ultimately kills the echo faster than a high ceiling.
If you have a room with echo problems, one sure solution is to add acoustical wall treatment. Alectro Systems installs the Fabricmate acoustical treatment, which is famous not only for it's excellent sound dampening but also it's great appearance.
By paying careful attention to the sound system design, we can improve intelligibility quite significantly. The important factors include:
1) Install accurate speakers which provide controlled dispersion angles and even coverage.The speakers must be selected and installed to provide accurate sound and project it evenly throughout the seating area of the room, and not into the ceiling where more echo is produced.
2) Use the right microphones for each application.By using microphones which are carefully selected for accurate sound reproduction and proper pick-up and proximity characteristics we can greatly improve intelligibility. There is nothing worse that muddy sounding microphones or speakers to destroy intelligibility.
3) Use a speaker delay system in large rooms.In larger rooms with front main speakers and fill-in speakers part way back, or under a balcony we use a digital delay system to "time align" the speakers. Without this, even more echo will be produced artificially.
Contact Alectro Systems to help you with your Church Sound.