Audio 101 – Acoustical Treatments – Churches & Large Halls – Part II
As mentioned in the previous article on Studio Acoustics, a big misconception about church acoustics is that equalization alone can fix sound problems. In reality, the most common sound issues for churches are most effectively addressed in the design and construction to ensure the space provides the performance you need. The question is what performance do you need?
A worship space needs to have balanced acoustics to support both effective communication and listening during the message, and some form of music during the service. In addition, the space must have a quiet heating/cooling system. The greatest challenge is determining and defining the type of room performance needed to effectively support sermons, unamplified music, and amplified music. Each of these conditions requires a different design criteria and acoustical approach, which can require a careful balance to satisfy the minister and music director.
To address these two common challenges, I discussed the design approach and solutions with two professionals, Erik Miller-Klein, PE, an Acoustical Consultant and Associate Partner at SSA Acoustics, LLP based in Seattle Washington, and John Ark the Product Development Manager at ATS Acoustic located in Piper City, Illinois. An acoustical consultant, or engineer, provides design assistance for architects, engineers, and homeowners to ensure sound and vibration are considered before construction, and provide cost effective diagnosis in existing constructions.
The size of the room determines the type of treatment, according to Product Development Manager John Ark. ATS Acoustics offers acoustic panels of all types. John says, “Smaller rooms are different from large rooms. Smaller rooms are more problematic with low frequency room modes; whereas, larger rooms are mostly about controlling reverb.”
Erik Miller-Klein said, “Speech intelligibility is significantly impacted by reverberation time within churches large and small. The large area of the average church generally has a long reverberation time, especially at low frequencies, which can make spoken words and amplified music sound muddy, though they can also provide good listening for organ and choir music. The most common issues are decay of sound due to distance, and excess reflections due to the large volume and hard surface finishes. Depending on the acoustic goals for the room, too much low frequency sound absorption from the panel absorption of the drywall on studs can also be an issue. With respect to speech intelligibility, if someone is too far back from the sound, and the space does not effectively reinforce the sound, they will not hear as well as those closer to the sound source. Much of this sound reinforcement can and should be done with the initial design of the spaces shape, constructions, and finishes.”
John Ark mentioned, “For the church using school gymnasiums, the challenge is that most of them are multipurpose rooms, supporting everything from basketball games to dinners and weddings. Treatment can be applied with baffles hanging from the ceiling, and wall panels on the upper level of the wall. However, that still can leave problems by ignoring the lower walls. A more dense material can be used on lower walls which will withstand basketball players. Most of the panels are pretty resilient; however, they can still get dirty from too much human touch. There are mobile options called studio stackers which can be moved into place for Sundays and special events.”
There are a range of sound absorption and room shaping choices that can be made early in the design to satisfy the use requirements. Mr. Ark mentioned, “ATC Acoustics has a wide range of materials and panels that can be integrated into a range of spaces.” Mr. Miller-Klein states that “There are options that can provide sound absorption to seamlessly fit the historic or unique aesthetics of your venue. There are materials that can be stretched over large spans or spray applied for unique conditions and applications.” Erik recently worked on an unusually-shaped church in which the congregation did not wish to alter the look of the inside during renovation. Without changing the look of the church, a stretched fabric sound absorptive panel installation was used, (Shown Before & After In The Photos Below), which provided over 50% greater sound absorption and significantly improved speech intelligibility. The congregation and staff have been very pleased with the results.”
There are a range of options that can be professionally installed, or completed by a congregation with the desire to do-it-themselves.
What about the positioning, or location of the sound board?
I have been to several churches, including my own, which has the sound booth in the back of the room, using an open window frame, elevated about fifteen from the floor. Additionally, I’ve played at other facilities where the sound board is located at the rear of the room on a balcony. This is very problematic. People mixing sound do not hear what those on the floor are hearing. If you are using a digital board, I highly recommend using a remote laptop or iPod, go to the floor, and set your mix from there when listening to the band.
According to John Ark, “The best mixing position is the 38% rule. This general rule states that the best listening position in any room is 38% from the front or back wall of a room. Therefore if your room is 100 feet long, setup your soundboard 38 feet from the rear of the room for an optimal listening position to mix and record the band.”
I asked Erik Miller-Klein about band location. “Many historic churches are rectangular, but many modern churches are fan shaped. Each of these spaces has its own unique challenges and advantages. A rectangle is best for speech intelligibility and with controlled reverberation a wide range of music. The fan shaped space can provide good speech intelligibility with sound reinforcement or shaped reflectors, but requires more sound absorption and provides better performance for amplified music rather than acoustic music.”
Erik said, “Early reflections are important to reinforce acoustic music and speech for non-amplified applications. This is the distance from both the source to the audience, and also the shortest distance off of a wall or ceiling. Generally, the shortest reflected path is from a side wall in a rectangular room. That is why concert venues and historic churches tend to be narrow rectangles, because although you could be sitting a good way back in the hall, the walls are close enough to you, that the side reflections support the sound, and are not delayed enough that they don’t distract from the sound… that’s the balance you’re looking for.”
Would you treat a location the same for all sound?
Erik Miller-Klein says, “The biggest challenge for churches is balancing acoustic performance between speech and music. If your concern is associated with sound between rooms or from outside sound sources, then walls, floors and other assemblies must be treated to reduce this impact; the sound absorptive treatments suggested for reverberation time are not effective for this condition. A room designed for speaking or congregational singing requires a different noise reduction approach compared to a room designed for choir and organ music.”
ATS Acoustics offers a free room analysis and helps guide you through options within their catalog to fit your needs. They offer customized panels which are not only effective, but have a variety of options to assist your facility.
SSA Acoustics is an acoustical engineering firm that provides design and mitigation support for architects, engineers, and owners throughout the United States. They focus on the design of schools, multi-family buildings, medical environments, churches, commercial/civic buildings, and noise control for manufacturing environments. Erik states that most acoustic consultants often save you money by guiding you to find the most cost effective solutions to your issues, and assistance during design often saves up to four times the construction cost compared to post-occupancy mitigation.
So now that you know there are different approaches and methods use. Here are some final thoughts and ideas. Erik Miller-Klein mentioned methods to blend fabric with your facility to effectively control sound. John Ark and ATS Acoustics has a different approach which uses visible panels to blend or use as artwork, called “Art Panels.” Send ATS Acoustics a graphics file, and they will print your artwork bigger than life on each panel.
So, here’s a great idea to get your room treatments done without asking your church to come off the church budget. Approach the congregation to sponsor panels. I’m not talking businesses on the church walls, but the church symbol on the top of the panel with an “In Memory Of…” at the bottom. Members can offer a dedication to their loved ones, and the church gets sound treatment.
I thank both men and companies for their candid approach and insight. Both offer different opportunities and approaches; however, they both conclude that if you have a room without treatment, you have sound problems with cannot be cured with electronic chemistry alone.