We are often asked, “what acoustic treatment do we need?” or “how do we know what to do to control the echo in our auditorium?” Let me walk you through some of the terms used as well as some of the tests that help determine the acoustical treatment needs in your facility.
The echo we often talk about in a room is more commonly known as “reverb” and is measured by how long the reverb (echo) takes to decay (silence) from when it started. Go into a room and make a loud clap; then, measure or count how long it takes before that initial sound is inaudible. This tells you the amount of reverb you have in that room. Reverb is a result of hard parallel surfaces. For example, in a gymnasium, you normally have high reverb because the side walls and end walls are hard parallel surfaces. To add on top of that, there is normally a hard floor and parallel ceiling. Most gymnasiums have a reverb decay time of 2+ seconds, and it can be difficult to understand what is being said.
Having shorter reverb decay time in a room creates an environment that makes the space sound clear and intelligible. It allows the listener to be more engaged in what is being said and done on stage. With today’s audio technology, it is much easier to add a bit of reverb back into the music when and if it is needed. Normally, 1 second or less of reverb is preferred for a classroom or space where clear intelligible sound is needed. For an auditorium, theatre or space where music is performed, 1.5+ seconds is preferred. Keep in mind that the more reverb you have, the more distant the source will sound. In some cases, like music performances, higher reverb is preferred, but for most speaking engagements, a shorter reverb time is desired. Once you go past 2 seconds of reverb decay, both speech and music become less intelligible and harder to understand.
There are a couple of ways to help reduce reverb in a room. One way to treat it is to break up the parallel surfaces with angles or varying surfaces so the sound does not just bounce and reflect directly back all at the same time. In some gymnasiums and auditoriums, the ceiling has open ductwork, trusses or other structural materials to help break up the sound so it is not bouncing directly back to the floor. Another way to treat a room is by adding acoustical panels that will absorb sound and stop it from bouncing back. There are many sizes and types of panels that need to be considered to pick the correct ones for your facility. Overall size, thickness, density and surface materials all determine how much they absorb as well as what range of frequencies they absorb. Adding the correct type, number of panels and in the correct locations around the space can help control the amount of reverb and provide a good listening environment.
For most church environments, it is as equally important to consider how things are going to look as well as how they will sound. Acoustic panels can be strategically placed and designed around the architecture as well as color so they can both blend in and enhance the way the room looks and sounds.
Our goal is to help create a comfortable and pleasant environment that keeps people listening and engaged. Let us know if you have any questions about the acoustics of your church and space as we would love to help you determine the best solutions and plans for your facility.