Problematic Sound in Your Sanctuary?

How the most important part of your PA system may not actually be a part of your PA system.

Audio production is the most complicated and subjective area of technical production ministry in a house of worship. It also is one of the most non-intuitive areas. What may seem to be obvious answers to an audio challenge can easily make the problem worse.

When the sound in your sanctuary or auditorium is problematic, the first thing to get blamed is the PA system—or the second, if the audio techs aren't being blamed first. But as often as not, the problem isn't with the PA systemit may be the room itself.

PA systems have two major components: the electronics and speakers; and the acoustical properties of the room in which it's installed. The room has a huge effect on how effectively the PA system works and how well the room sounds. Sadly, oftentimes one of the first things that gets cut from the budget of a new building project or renovation is work relating to acoustics.

The Problem

So, what do bad acoustics sound like?

"If a pastor’s in a space where the acoustics are not conducive for preaching," says Robert Rose, a senior consultant with Idibri in Dallas, Texas, "you can have echoes that are distracting to both the congregation as well as the pastor. In fact, you can have echoes just from the spoken word without the sound system involved at all. This is a detriment to the intelligibility of what's being said. You may also have a room that’s just overly reverberantthe words all start to run together. This results in the destruction of enunciation and clarityyou simply can't understand what the words are that are being spoken."

Acoustics problems are also not uniform throughout a room. "Sometimes the sound coverage in one area is lacking compared to other areas of the same room," says Neil Shade, president and principle acoustic consultant at Acoustical Design Collaborative in Towson, Maryland. "We do a lot of speech intelligibility measurements when evaluating a room. We often find that the worse spots within a room are frequently in the center and center front seating areas; the better areas are often at the rearmost seats. This is because you have a localized sound reflection off the back walls that arrives at your seat at a time that improves intelligibility instead of hampering it."

Churches with a very traditional choir and organ style of music program have additional acoustical challenges. "For traditional music, it’s generally good to have a longer reverberation timethe music sounds better in those cases," adds Shade. "However, the longer reverberation time negatively affects speech, and is also poor for contemporary music. If we have a church that desires to have both traditional and contemporary music, a compromise has to be made in terms meeting both needs."

For contemporary music, poor acoustics can raise different issues. "Often the music will sound loud and harsh," says Rose. "even if it’s not actually very loud. If you can correct the acoustics problems that are causing this, you may find that you can run the system louder and not get the same complaints."

Clearly, acoustics are something that should not be taken lightly. But what can be done to deal with acoustical issues?

Acoustics By Design

An auditorium or sanctuary can be designed to avoid the worst of the issues, and this involves engaging an acoustician early in the process.

"An acoustician is needed after the initial concept design and a general plan is made," says Shade. "We should come in during the schematic design phase. That’s where we can identify any issues with the concept the architect has come up with."

"The first goal is to understand the priorities," adds Rose. "What is the style of worship? Then you start to come up with acoustical solutions. You look at the core room shaping and interior volumedoes it fit the worship style? Rectangular and with more volume works well for a traditional space; for contemporary, fan shape works well for communication as it minimizes the distance to the people in the room. You want to avoid large flat back walls; curved walls are even worse as it concentrates the sound from the PA system back to the stage. One of the most common things we see now is terraced seating at the rear.

This creates better sight lines for those seated at the rear and minimizes the height of the back wall. It also adds more absorption into the room as the human body will absorb sound. Using upholstered seats helps absorb sound even when the seat is unoccupied."

"The ceiling is a good target for controlling acoustical issues," continues Rose. "It's the largest plane in the auditorium. You can use it to cut down the height and reduce room volume. Its configuration can be useful to break up low frequency standing waves. And, it's also an important element in congregational worship. If hearing the congregation worship is important, this usually comes via the ceiling. The acoustician needs to strike a balance between making the room dead for high-impact worship and allowing to have some reflection to support congregational worship and response."

"You also want to consider things such as where the HVAC equipment will be located, and where the youth space is relative to the main auditorium," says Shade. "Sound from these locations can significantly bleed over into the main auditorium. These are problems that can be completely avoided through space planning. If these aren’t caught upfront, it upsets the apple cart with regards to everything in the design and construction process that follows. If not addressed in the early design phase, it’s a tough sell to correct them afterwards."

While many architects understand and embrace the need for an acoustician on a project, there are those that do not. "If the architect says they can deal with the acoustics by themselves," suggests Rose, "the client should be concerned. You really need an acoustical expert on the project team."

However, we can't make that a blanket statementsome architects do have a grasp of the issues. "It really depends on the architect," says Shade. "If they do the same basic thing in every design, they may have it down and a dedicated acoustician might not be needed." At the very least, the client needs to investigate this and make sure that the right specialists are brought into the project and at the right time.

Fixing the Problems

While addressing acoustical issues at design time is ideal, not every church has that option. Many churches purchase existing buildings, and the shapes of the rooms are already literally cast in concrete. And even in a well-designed space, there are still acoustical issues that need to be addressed after construction is complete.

"An often-overlooked element is to control the energy around the loudspeakers," says Rose. "You want to get absorption above the speakers to control that first reflection. This should be done in conjunction with making changes to the acoustics of the room via absorption panels for midrange and higher frequencies, and bass traps for lower frequencies. You also need to design the sound system to minimize the negative impact of the acoustics."

Wall panels are usually just a few inches thick, are available in many sizes and colors, and many are used to cover most of a wall that would otherwise reflect a lot of sound. There are manufacturers that will create panels for you with pictures printed on them, to give it a more artistic look.

Bass traps are larger triangular pieces of absorptive material that fit into corners of the room. Corners are where lower-frequencies tend to build up, so these are the logical places to put such material.

Sound System Design and Acoustics

"There are a number of approaches to sound system design that can alleviate acoustics issues in a room," says John Monitto, director of business development at Meyer Sound in Berkley, CA. "In a traditional environment, you can go to a more distributed design, reducing the impact of bad acoustics by using more loudspeaker devices in a distributed manner such that each speaker covers a small, controlled part of the room. Another option is an old design called a pew-back system, with speakers mounted on the backs of the pews in every or every-other row. A third option is the column array mounted on the walls or other vertical surface near the front of the church. These radiate little energy outside the vertical beam of coverage, so it focuses the energy on to the congregation and off of difficult surfaces."

"If it’s contemporary worship space," continues Monitto, "you really need a space with good acoustics. There’s almost nothing you can do in a bad acoustic space to make that work well. You still end up over-exciting the room. You do the best you can to select components that keep the sound focused on the congregation and off the walls and ceiling."

Mixed Use Spaces

If you are a church that conducts a variety of worship service styles, the ideal would be an environment that has variable acoustics.

"The use of curtains that can be extended and retracted can change the acoustical response of the room," explains Rose. "Another option is motorized acoustical banners."
The best (and most expensive) solution for supporting variable acoustics is to start with a room that's designed to be as acoustically "dead" as possible, and to use an electronic system to create the acoustical environment you need for any given music type. One such system is Constellation by Meyer Sound.

Constellation uses many microphones and loud speakers that are distributed around the room, combined with special signal processing, to re-introduce early reflections back into the environment, and from the right locations in the room.

"Early reflections are like having an orchestra shell around you," describes Monitto. "A shell lets the various sections of the orchestra hear each other quickly. When you have good early reflections in a concert hall, it creates a closer intimacy between the music and the listener, and it helps the congregation to hear themselves better."

Many a church has wasted significant resources in replacing a PA system because it didn't sound right when the problem was in fact the room itself. Hopefully this article has demonstrated the important role acoustics plays in how your room sounds.

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