Intelligibility is quite possibly the most important consideration in designing, modifying or updating a worship space. If a congregation is not able to understand the pastor’s voice, then how will they hear the gospel? If a congregation can’t understand the words of the songs, then how will they hear the gospel? Notice the theme?
If you are interested in learning more about acoustics for houses of worship, check out the following session, "Acoustics - The 'Sound of the Word Matters'," slated for the WFX Conference & Expo on November 14 in Orlando.
Amplifiers, speakers, microphones and audio mixing consoles are not the only pieces to the puzzle that together that can add up to how good a sound system is. “Good” is a subjective term anyway, but I think everyone could agree that being able to clearly hear what is being amplified is a basic standard, one that all sound systems should meet.
In rooms lacking proper acoustic treatment, problems such as standing waves and flutter echoes will often arise. Standing waves cause an inaccurate bass response, because of the build-up of bass frequencies at walls and corners. Flutter echoes occur when sound bounces back and forth between two parallel walls.
Standing waves are best treated with acoustic treatment on the back wall(s) of a worship space, while flutter echoes are ideally treated by placing acoustic panels staggered on opposite walls. For example, if you place a 4-foot-by-2-foot acoustic panel on a side wall, do not place a panel directly across from it. This setup allows for sound to hit a wall, bounce to the other side and be absorbed by an acoustic panel.
Hiring an acoustic designer for your room is the best option in getting the proper sound out of the space, but if your budget doesn’t allow for professional input on such a project, there are resources available for treating the room yourself.
There are companies online, for example, that sell acoustic treatment. Keep in mind, though, that some companies’ products are quite expensive. If you are on a tight budget, there are also DIY options that can be found online. Most acoustic panels use Owens Corning 703 insulation for absorption. The 703 insulation is made up of a rigid fiberglass, and comes in various thicknesses. Typically, it cannot be purchased at big box home improvement stores, but can be easily found online.
With the thought of standing waves and flutter echoes in the back of your mind… The easiest way to determine where to place acoustic treatment in your worship space is to find any walls at which speakers are directly pointed; put absorption on those walls.
The next walls you should consider treating are side walls that could reflect sound from the speakers. If your room is square or rectangular, then you will need to treat the side walls, more so than in a fan-shaped room.
To determine the placement of acoustic panels in a recording studio, sit in an ideal listening position and have someone place a handheld mirror against the walls and slide it around. Acoustic treatment should be placed anywhere the person sitting in the listening position can see the speakers in the mirror. Since a worship space has more than one listening position, this technique isn’t as effective; however, you should consider the hard surfaces that play a part in reflecting sound to the congregation.
The ultimate goal is for the listener to hear more of what is coming out of the speakers, than what is bouncing off of the walls. Some natural reverberation is desirable, to avoid having a completely dead room; however, you want to be sure to avoid flutter echoes and standing waves.
When all else fails, walk around your room, listen for the spots that sound the worst, put acoustic treatment on the walls that is closest to that spot and determine whether or not the sound has improved following those adjustments. Though an understanding of certain scientific principles will improve acoustic design, there is also artistry to the process.
For further reading on acoustics, I highly recommend “Master Handbook of Acoustics,” by F. Alton Everest.