Acoustics in church architecture: A virtuous relationship

by brittney_cutler | November 1, 2021 9:58 am

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By Buddy Siebenlist

Religious services are carefully customized to deliver timeless and transformative messages evoking thought and contemplation. To produce the maximum effect, they should stimulate the senses as well as the mind.

The sights and sounds of the churchgoing experience should enhance the feeling of being immersed in an inspirational environment, where hope is generated, and burdens are lifted.

In a worship-centered context, the importance of sound and its effect on the listener cannot be overstated. This article does not look at content of the music or spoken messages, but to the actual quality of the sound itself. People associate the churchgoing experience with a particular atmosphere, and a church’s acoustics play a foundation role in creating a unique and memorable ambiance.

Complexity of the church acoustical model 

Fundamentally, a church is a place of sound. Acoustic design is a primary consideration, whether the church space is a worship center, a sanctuary, a chapel, a Sunday school classroom, a fellowship hall, or a family life center. Consequently, the architect must understand and skillfully design the auxiliary physical elements of the project space to ensure acoustic performance of the highest possible quality.

Churches are constructed from a diverse mix of materials. Frequently designed for multiple uses, churches may incorporate stone, marble, glass, concrete, brick, and wood into their building plans, all of which have unique acoustic characteristics. This makes for a complex acoustical profile, as do some of the unique features churches often include, such as high ceilings and large glass windows. The materials used inside churches add another layer of complication to the overall acoustic picture.

To obtain accurate calculations of sound quality, church architects must create a realistic model including all the above elements. They can now create 3D models that visually represent a specific church’s acoustical characteristics using modern software programs.

Archaeological acoustics in churches

Whether working on new projects or remodeling existing structures, church architects are guided by the universal principles of architectural acoustics. As the design process unfolds, acoustical considerations will remain front-and-center. Here are some factors they must consider:

• Suitability for both speech and music. Standard church services feature sermons and prayers broken by musical interludes. Concerts may be held in churches, involving touring groups, bands, orchestras, church choirs, children’s performances, etc. Consequently, the design of a church auditorium should be carefully customized so speech and music can be heard clearly from everywhere without distortions.

• Material absorption and reflectivity capacities. Building and finish materials of all types will reflect and absorb sound waves. As a result, a church’s acoustical profile will emerge from neutralizing or counterbalancing the effects of everything it includes as a part of its overall physical structure, both outside and inside. Deliberate choices by the architect will customize this result. If care is not taken, the worshipping experience may be disrupted by echoes or reverberations or by the excessive leakage of sound from one space into another.

• Consistent sound diffusion. Sound should be distributed in occupied areas as equally as possible, avoiding low-sound areas where hearing is difficult and high-sound areas that can cause discomfort to the listener. Acoustical ‘hot spots’ and ‘cold spots’ in a church can leave some worshippers straining to hear, while others struggle with headaches from an ear-splitting din.

• Compatibility with video and audio systems. Larger spaces may require video and sound systems to ensure those far from the stage or podium do not miss anything. Acoustical design choices should still be as worshipper friendly as possible, but they should enhance rather than clash with the expected output from supplementary audio systems.

• Changes based on occupation levels. The presence of people will change a building’s acoustic properties; the larger the gathering, the more dramatic the effect. This must be compensated for during planning, so the acoustics remain good regardless of how many people are packed into a church’s sanctuary, social hall, or meeting space.

• Interior background noise. One of the biggest concerns here is a church’s HVAC system, which could be required to run nearly full-time in some locations. Wise and acoustically astute architectural choices can decrease or eliminate the likelihood anyone will be bothered by a steadily running furnace, air conditioner, fan, or ventilator, or by any other type of background noise that might be present.

• Environmental noise from outside. This can be a significant problem if a church is constructed near a busy thoroughfare, park, sports field, or other popular public destination. Church architects must know a lot about the environment where their projects will be constructed, so they can take steps to ensure indoor worshipping spaces are kept as secure as possible from the unwanted incursion of outdoor noise.

• Design preferences of the client. Each new church will have a unique acoustical footprint, which will depend mainly on the specific design requests made by the client. A cookie-cutter approach to acoustics will not work, which is why experienced church architects spend a significant amount of time factoring acoustical principles into every calculation they make.

Churches create specialized and unique acoustical challenges for architects, who must pay careful attention to detail throughout the design process to make sure those challenges are met.

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Sound absorption and diffusion explained

For worship service assembly, sound absorption, sound reflection, and dispersal (diffusion) are necessary in some combination depending on the church’s goals. A healthy balance must be sought, avoiding extremes that are likely to create an acoustic profile inhibiting the church’s inspiring message transmission.

In general, churches are built with high reverberating qualities. As a result, interior design choices are frequently made in part with an eye on reducing reverberations. Interior materials’ sound absorption and diffusion properties must be extensive enough to eliminate potentially disturbing echoes while also ensuring guests occupying the farthest corners of a worshipping area can still hear everything clearly.

Sound absorption is typically the goal in spaces used for most contemporary worship services, recreation assemblies, education, and administration. The average noise reduction coefficient (NRC) for these spaces should be around 0.8, depending on the size and design of the area. Ceiling absorption is more effective in large spaces, and wall absorption is more effective in small rooms. Reverberation time (or echo) is calculated as 0.05 (room volume) divided by the sound absorption capacities of the room.

Diffusion in sound dispersal promotes uniform distribution of continuous sound and improves the sense of ‘liveness,’ which is very important in performing arts. Objects and surface irregularities accomplish this. In the design of these spaces, subtle, non-parallel surfaces eliminate echo and distortion for clear speaking. Specific materials will be specified to redirect and diffuse inspiring music. Sound dispersion can be boosted through strategic acoustic wall placement and the use of appropriate acoustic materials.

Generally, spaces used for speech require 3.4 m² (120 sf) per audience seat, while spaces used for music require 7.65 m² (270 sf) per audience seat. If a particular space will be used for both (as worshipping areas in churches often are), the architect will seek a comfortable balance between the two.

To get a better handle on cumulative acoustical effects, church architects will use a Ray diagram. These sketches track both direct and reflected sound paths and help determine whether annoying and distorting echoes are likely to be experienced inside an enclosed space. If a reflected sound path is more than 10.4 m (34 ft) longer than the sound’s direct path, this will create a noticeable and undesirable echo for those inside the church auditorium.

Acoustical factors for architects to consider

From an acoustic perspective, many spaces are designed to make it easy for occupants to have intimate conversations, which means high levels of sound absorption are required. In lecture halls, sound diffusion is critical since people sitting in the back must hear the lecturer. In concert venues, sound reverberation is encouraged because it enhances the impact of live music.

In seeking the ideal balance between all three essential qualities—reverberation, diffusion, and absorption—churches strive to be all things to their communities. The most acoustically beautiful church would be conducive to music, lecturing, and one-on-one conversation, thus catering to none specifically but to all simultaneously. A special effort will usually be required to boost a church’s capacity to absorb and diffuse sound since a potential lack of reverberation is seldom the issue.

Ideally, absorption and diffusion levels would be increased by wall and ceiling construction types and by adding appropriate interior features to worship and gathering spaces inside a church. If this proves inadequate, installing commercially produced absorption and diffusion panels might be necessary, which can be applied to walls at strategically chosen spots.

In churches, effective sound management can be further complicated by controlling unwanted and intrusive sounds. For example, when church services are at capacity with worshippers or guests, they can be quickly filled with the sounds of whispered conversations, coughing, footsteps going up and down aisles, people shuffling around in pews, and the noises of restless children. If there are roads or commercial areas outside, traffic sounds can also penetrate church walls. A church’s HVAC system can add a significant amount of background noise if wintertime or summertime services require them to be kept on full-time. All this sound is distracting and unwanted; it can interfere with a listener’s ability to hear words spoken from the pulpit.

It must also be acknowledged that church members, the pastor, and church administrators have opinions about how a church should look and about the emotions it should evoke. Stray too far from those tradition-shaped expectations in search of improved acoustics, and the congregation is likely to react negatively. This means church architects will not have a green light when adding sound-absorbing or diffusing features to their building plans but will be restricted to design choices staying within certain traditional bounds.

There is another added complication. In the modern day, churches have embraced the principles of multipurpose design and construction. This means a room, hall, or gathering area used for one purpose in 2021, might be used for something else entirely by 2026. In some cases, a room, hall, or gathering area might be designated as multipurpose from the outset, meaning churches plan to use them for different types of activities right from day one.

The acoustic ramifications of multipurpose may be minor or significant, depending on the range of activities that might take place in a particular location. In some cases, churches might have to add acoustic panels or sound diffusers once the area has been repurposed. They might even have to add more reflective surfaces if more reverberation is needed to increase sound amplification.

Ultimately, each church construction or remodeling project is unique. No two churches or church campuses are built exactly alike, and no two congregations are precisely alike, either. On each new project, a church architect’s job is to create a blueprint with a detailed and customized acoustic profile, which has been tailored as precisely as possible to fit that church community’s current and anticipated future needs.

The science of sound decoded and applied

The soaring, monumental cathedrals of medieval times are marvels of acoustic perfection. Churches are no longer being built with such awe-inspiring dimensions. Nor are tried-and-true models being followed that have been guiding community construction practices since the 1800s. Expectations have changed with worshippers’ needs, architectural budgets, time scales, and land availability. Since modern churches are no longer iterations of pre-established themes, designers must rely on an advanced understanding of architectural acoustics and the science of sound to stay ahead.

The acoustics are the heart and soul of the church. When the architect gets it right, they can enhance the emotional, intellectual, and spiritual impact of a church sermon or musical performance, helping to make church services a truly unforgettable experience for worshippers.

Author

Buddy Siebenlist, AIA, Founder of Siebenlist Architects, has more than 25 years of architectural design experience with over 100 designs of churches and other projects accomplished. Siebenlist is the architect of the Tabernacle of Glory’s project in North Miami that is underway and nearing completion. Siebenlist was Director of Facilities at a megachurch with over 22,000 members, K-12 School, Day Care, Restaurants, and TV/Radio Media which has provided him with unique insight and understanding about the operation and agenda of churches of all sizes and ministries. He is a resolute problem-solver, with a reputation for bringing projects to fruition. He can be reached at buddy@siebenlist.com.

Source URL: https://www.constructionspecifier.com/acoustics-in-church-architecture-a-virtuous-relationship/

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