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Intelligibility and Acoustics in Worship Spaces

Many of us have heard the scripture, “Faith cometh by hearing and hearing by the Word of God.” If faith comes by “hearing the Word of God”…I wonder how many churches are presenting to some degree a faithless message because the congregation cannot clearly hear the pastor. There are 18 references in the New Testament of “let him hear.” The implication is that the person who is listening should focus or give attention to what is being spoken. Pastors and worship leaders have a golden opportunity when a visitor or attendee takes a step toward the church by coming in the doors and making themselves available or even vulnerable to the ministry. The next step is ours. We are responsible to make every effort to ensure that they can understand the message. If the presentation is unclear, it is not the listener’s fault. They have done their part by coming; we must do our part to give them every opportunity to receive the message.

A question was recently asked, “What are the biggest problems encountered in churches when dealing with acoustics?” The answer is simple yet profound… understanding. Using the word understanding here can be a little confusing. I am not talking about the pastor’s vocabulary and sermon subject being way over the heads of the congregation. Nor that the music is so intricate that it boggles the minds of the rest of us. In this context understanding is actually hearing clearly and completely what is being said. This is often referred to as intelligibility. This is the one thing that most churches have big problems with and it holds people back in their worship services. Understanding means that you can clearly comprehend what is being communicated.

Regrettably, the most common complaint received from pastors, worship leaders, sound personnel and church members is that in one way or another, the congregation cannot hear what is being presented. Then the frustrated soundperson usually answers back by saying that he or she had it turned up plenty loud. Why couldn’t they hear? The key is that the listener is hearing sound; it is just unintelligible sound or misunderstood sound. The pastor is desperately trying to communicate the message, but there is something hindering the sound energy. What causes this loss of clarity? In most cases it is the room acoustics. But, before understanding can happen within the room, you have to recognize what is going on in the room acoustically. Sound a bit confusing? Let’s look at these “intelligibility robbers”.

There are several factors that cause intelligibility loss. The “bad boys” that cause most of the acoustic problems in facilities are echo and reverberation. An echo is a reflection of sound, arriving at the listener after the direct sound. We have all hopefully had the chance to shout “HEY!” at a canyon or the mountains and hear it come back a little later.

Reverberation can easily be defined as the amount of time it takes for sound energy to dissipate (bouncing around a room before being absorbed or running out of steam). Reverb can be measured by the time it takes the sound to decay 60dB. This is referred to as the decay time of a room or the RT-60. To put it simply, everyone has experienced these “bad boys” to some degree. Have you ever been in a gym or cafeteria and you could not understand what was going on, or had to strain just to make any sense out of the person talking to you just a few feet away? It’s as if you can almost make out what is being said but you are missing some pieces of the words or sounds.

The best analogy of this is to think of an older TV. The reverb could be like the picture being a little snowy and fuzzy, and echo like the ghosts and shaky lines in a bad picture. The image is there but that image is being distorted by these factors. When solved, the image is brilliant, crystal clear! Hearing in a room can be like this. Sound is being transmitted but there are interferences such as reflective surfaces, parallel walls and all sorts of things that are distorting your perception of the sound, making it fuzzy and unclear.

Many times churches spend multiple thousands on new sound systems and speakers only to find out the same problem is still there. Why? No one ever explained to them the importance of room acoustics. The room acoustics are the missing link between the presenter/sound system and the listener. Without the acoustical problems of a room being solved they will show up over and over, no matter what sound system changes are made.

The good news is, there is an answer! There is a solution so that the people can actually hear the pastor, worship leader, and any other element of a church’s worship service. The same acoustic principles apply to the large gathering, to the fellowship hall, to the activities center and all the way down to the Sunday school room. This is vital to understand because, after all, churches exist to help people, and to do that the people must hear the leaders of the church.

It is unfortunate that there have been facilities constructed for houses of worship where acoustics is the last thing on the minds of the decision makers. Although the primary purpose of this facility is to gather people together and communicate a message, many times the acoustics are one of the first things to get cut from the budget to upgrade carpet, seating or some other décor item. They simply do not understand the decision that they are making. This would be like building a movie theater and deciding to cut out the speakers from the budget to add better seating. It would feel nice while you were watching, but no one is going to hear a word the actors are saying. This happens in many churches when the acoustics are cut from the budget or not addressed at all. Basically we have allowed the “bad boys” of acoustics to take over our services.

Bad room design and shapes usually cause most of the problems. However, even in the best-designed rooms there may still be a need for acoustic treatments. It is wise to address the acoustics on the front side of any project, even though the acoustical cures can still happen after the room has been built. It may be a little trickier than if it had been dealt with on the front side, but it can still be solved. With the right products and approach, in most cases you can still achieve an amazing acoustical environment.

I have had the opportunity of working with the best sound companies, system designers, acoustical consultants and architects in the nation on a daily basis. One thing they have in common (besides a great reputation and success) is that they will not even touch the sound system if the church is not willing to address the acoustics. They know if they take on the job and the acoustics are horrible, then the sound system is not going to perform well at all and the customer is not going to be happy. That means no repeat business or referrals.

All sound systems have to operate within the physical parameters of the room. It’s physics. The room will always color and have an impact on the sound. So, your room’s acoustics are either increasing or decreasing the intelligibility of the sound.

Acoustical cures in churches can help facilitate and sustain growth and, more importantly, people can hear the life-changing message that is being spoken! People will not keep coming back to an environment that is annoying, where they cannot hear or understand what is being said.

Just like you would hire a doctor to perform surgery, you can hire an acoustic company to diagnose your room and project a price to fix it. By reviewing the dimensions of a room, the walls and ceiling it is very feasible to find out what is needed to make your room a better listening environment. Now, about these companies that design and recommend; check their track record! Again, just as you wouldn’t want to go to a doctor that has a high mortality rate on his operations, you also wouldn’t want to use a bad consultant. You can usually get references, call on completed projects and see the quality of materials they use in their recommendations.

Here are a few tips when looking into acoustical products. First of all, not all panels are created equal. Every acoustic unit has an NRC (Noise Reduction Coefficient) value. This value lets you know how much sound it will absorb per square foot, or how well it performs. For instance, a panel that has an NRC of 1.00 will absorb twice as much per square foot as an NRC .50 panel. Most of the time you or a consultant will figure how many “sabins” you will need to solve your problems. A sabin of sound absorption is equal to one square foot of absorption of 1.00 NRC.

This becomes really important when determining if one proposal is better than another. You should not necessarily always ask, “What the cheapest price is,” but rather “what is the best value?” Using the same example above, if you need 1,000 sq. ft. of absorption material and the .50 NRC product costs $3,000 and the 1.00 NRC costs $5,000 for 1,000 sq.ft…then which one is better? It depends on how many sabins you need. Using 1,000 sabins, the second would be a better value because it would take twice as much of the .50 NRC products to equal that of the 1.00 NRC product. Thus, the first would actually cost $6,000, and the latter would cost only $5,000.

Unfortunately, what happens in most cases is that the owner decides to go with the cheaper price and unknowingly settles for only half of what is needed, and then ends up with a room that is still not solved.

Different products have been designed and engineered for specific purposes. There are diffusers that help to break up echoes and leave the reverb. There are absorbers that only absorb, and some that have diffusive characteristics built into them. Some have better fire ratings or better durability ratings.

With all the different types of products and different manufacturers, here is the best advice I can give you.

There are five basic ways that you can judge an acoustical product:

1. Performance (NRC)
2. Fire Rating
3. Durability
4. Looks
5. Price

If all five of these categories are considered and applied to your specific needs, then you will find the best value of product for your purpose.

Countless churches have purchased several complete sound systems, tried all sorts of different microphones and spent thousands on processing equipment and are still not happy with their sound and still cannot understand the words being spoken. When the room acoustics are properly solved their noise now becomes beautiful music, their pastor’s messages are more relevant than ever before, and the video and special presentations seem to pop now. How can people catch the vision of the church and move together in unity, if they can’t understand the pastor’s words in a service? Acoustics are important.

You can prepare the best sermon, the best music set, or the best video presentation, but if the acoustics are bad then you can’t clearly communicate your message. If you can relate to this article, I highly recommend adding an acoustics expert to your team to help you thoroughly look at and solve your issues. I often joke with pastors and say, “It is really important for your listener to be able to hear the word H’NOT’ in ‘thou shalt not commit’.” We laugh, but at the end of the day… whether we realize it or not… acoustics are vital!

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