Acoustics – A First Analysis
Nick Colleran, Acoustics First Corporation
SoundBytes Gear Head June/July 2009
A church’s physical size and structure, as well as sound requirements for the service, cover a broad and varied range.
The majority of churches require some acoustical treatment. And it is best to hire a trusted outside firm to handle the job (visit other churches where that firm has cured acoustical ills). That said, before hiring an independent professional to do a thorough acoustical analysis of your church, it is a good idea to get a ballpark estimate of what it will take to fix the problems. It can be done with about $3 worth of party balloons and some equipment commonly on hand: a camera and audio recorder. [By the way, dispel yourself of the myth that acoustical challenges – especially severe ones – can be cured by console equalization, or even “room EQ.”]
Here’s the information you need to provide an off-site analysis of your room acoustics:
This information allows the calculation of total room cubic volume, which is necessary to determine the existing sound absorption and derive the change needed to reach a desired acoustical result. Include length, width, height plus sides and ceiling peak.
What is the existing composition of the floor, walls and ceiling? Marble, carpet, wood, drywall, masonry, acoustical tile, drywall and plaster will all contribute their unique sound properties to the acoustical environment. The addition of acoustical material does not produce a change in total sound absorption by its full rating unless the surface being covered is extremely reflective. If the existing wall has some absorptive value, a new layer of acoustical material may provide only a marginal difference in absorption.
Is seating hard or soft? Padded pews will prevent a big difference in sound when attendance may be down – during summer vacation, for example. If all surfaces are hard (marble floors, wood ceilings, plaster walls and wooden pews) acoustics will vary more with attendance and season. Heavy winter coats will reduce echo whereas summer attire and fewer folks will provide less absorption, allowing more reverberation.
As implied above, there may be a need to compromise acoustics between perfect attendance and vacation time. How many people (maximum, minimum, typical) attend and how often? Do you want it to sound good most of the time?
“Everybody knows” may be accurate for the regular congregation’s awareness of the sanctuary and its furnishings, but it is not good to leave it to the imagination of others many miles away who may have worked on some very different worship spaces prior to your phone call. Pictures will “flush the buffer” of information stored from a previous consultation. Six “stills” (front, back, left, right, ceiling, and floor) will do the job.
Type of Service
One size does not fit all. Moving from traditional choir and pipe organ to a more contemporary service modifies acoustical needs. Congregational singing requires greater ambiance for comfort while high intensity praise and worship needs more absorption for control of sound. It is disheartening to have to add back reverberation after spending unnecessary amounts of money to get rid of it.
What are the complaints? Is it speech intelligibility or lifeless music? Often a complaint is given in the form of a conclusion as to the cause of the problem. A poll of the non-technical listeners will sometimes yield better raw input for acoustics than advice from the regular sound people who have been doing a work-around for months or years.
Reverberation Time (RT60)
This can be estimated with a loud, sudden noise such as a balloon pop, timed with a stopwatch from initial impact until no longer audible. If recorded, this impulse noise may be viewed and analyzed on a remote computer screen. Let the acoustical analyst know where the sound originates (pulpit, choir loft, center of sanctuary).
Listening to the sound and looking at its decay pattern, and then referencing both to what is seen in the pictures, will give a good idea of the overall acoustical sound environment, its causes and opportunities for correction.
Nick Colleran is a member of the Acoustical Society of America, Past President of the Society of Professional Audio Recording Studios (SPARS), former president of the Virginia Production Services Association (VPSA) and is currently active in acoustical design for houses of worship, new acoustical products and performance venues. He is a founding principal of Acoustics First Corporation, a manufacturer and distributor of acoustical materials – and sponsor of the HOW-TO Church Sound Workshop tours.
Copyright 2009 by the author and Acoustics First Corporation. Used by permission. N090609FirstAnalysis.
This article “Acoustics-A First Analysis” written by Nick Colleran, was excerpted from www.howtosound.com, July 2009. It may be used for study & research purposes only.
This article may not be written by an Apostolic author, but it contains many excellent principles and concepts that can be adapted to most churches. As the old saying goes “Eat the meat. Throw away the bones.”