In churches, synagogues and worship centers large or small, words and music can sound incomprehensible to the congregation if sound is not properly controlled.

Poor sound quality is common in churches because of an abundance of hard surface materials. Brick, marble, stone, tile, glass, wood and sheetrock are all acoustically reflective. Sound waves bounce back and forth between parallel surfaces, creating a confusion of noise until they finally decay. Even the most strategically-placed speakers and microphones will not compensate for poor acoustics.

Every room needs some absorptive materials and some reflective materials to get the right acoustic mix for the room’s intended purpose. The challenge is to find that balance. Wall Panels are designed to absorb airborne sound energy and reduce a room’s overall noise, reverberation and standing waves—creating interiors that reduce the din without sacrificing the divine.

Treating Reverberation or Echo Problems in Your House of Worship

Sound control in a house of worship is required for understanding the spoken word and full enjoyment of the church sound system. Typically, the large volume and hard surfaces in the newer architectural designs create excessive reverb, slap and flutter echo problems for the church sound system. This reverberation problem reduces the speech the and creates problems for the church sound system. Acoustical Solutions offers various ways of treating these problems while maintaining the aesthetic look that a church desires.

Noise Control in a nutshell (for existing buildings)

Some spaces are not primarily designed with an acoustical function, but acoustics impedes other functions: these spaces are just too loud. The acoustical requirement for noisy spaces, such as cafeterias, work spaces, gymnasiums, and pools is straightforward: make them less noisy. There are two ways to accomplish this goal:

1. isolate the space from noise sources;
2. reduce reverberation.

It is always better, if possible, to control noise by removing a noise source. In the case of a cafeteria or gymnasium, however, the largest source of noise, people in the space, can’t be removed. However, there may be other sources of noise that can be removed to make these spaces quieter, such as air-conditioning units and – very common – drink vending machines with loud, built-in refrigerators.

Changing room surfaces to reduce reverberation is often the only practical solution for quieting a noisy space. The basic problem is to determine how to get in as much sound-absorbing material as possible at a reasonable cost while preserving aesthetics.

Churches & Synagogues

Churches offer an extreme example of the multipurpose space. Churches have several conflicting acoustical requirements during the same event. The acoustics during the service can’t be altered to meet the acoustical requirements both for organ and choir on one hand, and speech intelligibility, on the other. The differences are huge. Though these differences vary widely in their acoustical requirements, they share one fundamental acoustical requirement: silence, the elimination of background noise.

Furthermore, there are severe aesthetic constraints on church design. Architectural acoustics has to integrate into architecture. For example, hanging baffles and flying panels are an excellent tool for reconciling reverberation and clarity, yet church committees may be reluctant to consider such visible measures. These baffles and panels serve not only their acoustical function of providing clarity within a reverberant sanctuary, but also enhance the visual sense of space in the sanctuary: architecture plus acoustics equals architectural acoustics.

Some early traditional church design is well planned. These churches are modest in size, narrow, quiet, with side balconies. They work well for both speech and church music. Contemporary church design would benefit a great deal from careful study of these paradigms. Most churches require a sound system that is really integrated into the acoustics of the sanctuary.

Performance Spaces

There are three basic types of performance spaces:

Single purpose rooms

Multipurpose rooms

Rehearsal rooms

Though these spaces vary widely, they share one fundamental acoustical requirement: silence, the elimination of background noise.

Single-purpose rooms

The single-purpose performance space is a delight. Spaces with a focused acoustical function, such as concert halls, recital halls, and dedicated lecture rooms, offer a real opportunity for a client with a limited budget to achieve acoustical excellence. Limit the size, exclude background noise, focus the design around acoustical function, and excellent acoustics comes well within reach.

In real life, the true single-purpose performance space is rare. Nearly all performance spaces are multi use in practice, if not by design. Even dedicated concert halls are used for a variety of purposes.

Multipurpose rooms

Multipurpose performance spaces are often built to save the money it would entail to build several dedicated spaces. A school, for instance, that might be better served by a music recital hall and a speech theatre, builds one large, multipurpose auditorium because of cost. Since they are built for reasons of economy, multipurpose spaces are often too large, with budgets too small to provide what is necessary to make them work. The large, multipurpose performance space is one of the most difficult acoustical challenges, even under the best of circumstances.

The most common multipurpose spaces are churches and synagogues.

Rehearsal rooms

Rehearsal rooms, unlike most performance spaces, are usually too small. Sometimes, a music group that is too large or too loud will simply overwhelm the space. For these rooms, one needs a combination of sound absorption and sound-diffusing geometry that makes the room act like a larger room. Sufficient height is critical. A rehearsal room that has sound-absorbing surfaces, but lacks sound-diffusing surfaces will sound dead and unresponsive and will pose difficulties for hearing amongst members of an ensemble.

Sound Isolation

Rehearsal rooms are often located near performance spaces or other rehearsal rooms, and so require good sound isolation from these other spaces.

Background noise

Although background noise may not be as critical in a rehearsal space as in a performance space, breakthrough from other practice rooms, choir, gym or  mechanical (HVAC) noise can make all the difference in the acoustics.

Adjustable acoustics

Relatively uncommon but very helpful is the use of adjustable acoustics for a rehearsal room utilized by different types of ensembles. A small vocal ensemble needs a room with some reverberation in order to blend its sound. A band, at the other extreme, requires maximum sound absorption. If both groups must share the same room, adjustable sound absorption is the means for satisfying both requirements.

A Primer On Material Used For Acoustical Treatment
by Nick Colleran
 CHURCH PRODUCTION MAGAZINE MAR/APR 2004 Page 82
(www.churchproduction.com)

Recent times have seen dramatic changes in the quality and quantity of church sound. Much like live Gospel recording, the sound control of a professional studio is now needed in the church with a praise band. Scanning the radio dial. and not listening closely to the words, it is difficult to hear the difference between Contemporary Christian music and [secular Pop]. The message may be quite different but the sound and acoustical requirements are the same.

The sanctuary sounds "heavenly" for choir and pipe organ may be completely unsuitable for the higher sound levels of a modern worship service. At low levels, the sound of an acoustic guitar and voice will fade before it reaches the walls. Drums and amplified instruments will reach the room boundaries and what comes back from those surfaces can create problems. Such problems can only be solved with proper acoustical materials and design.

What are acoustical materials?
In the broadest sense, acoustical materials are anything and everything that affect sound or noise (unwanted sound) in quality and intensity. (My definition. These are sweeping generalizations that will hopefully make the subject easier to understand.)

Acoustical materials used for sound control generally fall into a few broad categories: absorbers, barriers, diffusers, and isolation devices. Not much has changed since sound was invented, except possibly that a few of us spell diffuser with "-or" these days.
Absorbers are sometimes called "fuzz" by acousticians since things that are soft and porous ("fuzzy") tend to muffle or absorb sound. The more porous pathways there are in a material. the better the absorption. The sound gets trapped and loses energy trying to find its way out and bounces back with much less intensity.

In commercial acoustics, the most prevalent absorbers for public spaces are compressed fiberglass (glass wool), often incorrectly called "70}" and rock wool (mineral fiber). Fiberglass is more prevalent in the United States while rock wool finds wider use in Europe. Both of these materials meet Class A (or Class 1) fire safety standards. These are most often found as the core material (substrate) in fabric covered panels.
For lighter absorption there are wall car- pets made of synthetic fiber. Floor carpet, although possibly a good absorber. does not always meet fire code for wall mounting where there is increased oxygen flow.

The most "bang for the buck" (or maybe it's reduced "bang" for less bucks), is poly- urethane acoustical foam. This is easily formed into wedge shapes by convoluting. The foam blocks are compressed by mating rollers and sliced by a straight blade. The resulting pattern is a three-dimensional surface with increased surface area. Some- one once told me that the surface area of one square foot of a four-inch anechoic wedge foam has a surface area of four and one half square feet. It is easy to see why absorption numbers exceed the 1.00 limit of a square foot of open window.

Unfortunately, foam has several drawbacks: flame, fume and fragility. While the acoustical foam used by the established brands should not be confused with the "foam used for acoustics" in the recent nightclub fire.

it will not pass code for public spaces, high rise buildings and most other applications. A foam substitute, cellular Melamine (white foam) will. This material developed by BASF and sold under several different trade names, is now being used in fabric- covered panels that have the added benefit of being able to be bent to conform to curves It has found wide use in ceiling tile configurations requiring Class 1 materials. Applied to the surface of the tile, it provides very high sound absorption and allows a variety of designs.

The next category, barriers, provides mass to block sound. The fuzzy stuff (absorbers) will prevent sound bouncing back to create flutters, echo, and sustained reverberation but it won't soundproof. It requires something heavy. dense and massive, with no openings to stop transmission.

In the early days recording studios used double layers of 5/8-inch "green board", a dense gypsum product to block sound. Lead foil was often included as a layer. When it came time to "get the lead out", mass loaded vinyl came into use. This is another product sold under many different trade names from several sources. Buyers are cautioned to check freight
cost since it is as "heavy as lead". That's why it works. One-eighth inch of barrier blocks more sound than a two-inch, solid core oak door. It is popular both for its effectiveness and the fact that is more forgiving to install than lead foil.

Diffusers (or diffusors) , are sound-scattering devices. They lower the intensity of sound by spreading it around rather than eliminating it altogether as an absorber would. I often refer to this as acoustical crowd control. breaking up or dispersing the sound that is "milling around" and causing trouble. There are several commercial units each with a different mathematical basis often determining its operating range. With properly designed diffusion a room will feel bigger and more open and it will be more difficult to determine where the walls are located since reflections return to the listener's ear at many different time intervals rather than one big" slap back", A church praise band will no longer be forced to play within the two tempos (one fast. one slow) corresponding to the timing of the bounce back from the rear wall.

Some more traditional diffusers, polycylindrical barrel shapes, are actually used more for bass trapping. Bass trapping is a counter-intuitive term. A bass trap actually prevents the lower frequencies from reflecting back out-of-phase and canceling. Bass build-up heard in the corners may actually be a perception due to absence of bass in the middle of the room. Properly sized traps can tune a room's response, something that cannot be accomplished electronically. (A frequency boost with an equalizer will also boost the out-of-phase cancellation at the same frequency, unless the room is correct.)

Although there are more variations, the last element we will discuss is isolation devices. Sound travels through structures. For this reason. recording studios use a separate foundation slab for control room and studio, The ability to isolate sound gets worse as frequencies get lower. In fact. the bass can often be louder down the hall than near the source.

To avoid this problem, speakers may be hung with isolation hangers which are basically acoustical shock absorbers. Drywall may be hung on resilient channel with recently developed isolation clips (another product sold under several names as a distributor house brand). Floors may be floated on neoprene or other resilient pads. Where the floor cannot be floated. heavy platforms on isolation pads for drums and electric instruments, will prevent transmission at the source. (The author once built a sand-filled platform for a drum booth and floated it on nine truck tires to prevent the bass "kick" drum vibration from traveling through the floor and exciting the acoustic piano.)

All of these topics require much more space for an in-depth discussion than this article allows. I could say that a book could be written on this, but many already have. Hopefully, there is enough here to encourage your reading.

Religious Facilities Across the country, religious services of all kinds are increasingly including vocal and instrumental performances. Whether a church or worship center is large or small, reverberation is often a problem in these spaces because there are so many hard surfaces for sound to bounce off of. Good acoustical control is vital to ensuring that sermons and music are heard and enjoyed by everyone. ArtUSA offers a variety of products to solve the acoustical problems of religious facilities. We have products  made from Class 1 fire-rated willtec® foam and and MW S-2000 series are available in an array of colors, textures, and styles to fit any interior setting.

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