Last night I had the privilege of attending the Outcry Tour at the Van Andel Arena in Grand Rapids Michigan. The event had praise and worship artists, Elevation Worship, Jesus Culture and Martin Smith, Kari Jobe and Hillsong Worship with speaker Brian Houston pastor of Hillsong Church. We sat on the floor level about midway between the back of the arena and the stage. As a church A/V/L person I was mesmerized by the lights, overtaken by the visual effects displayed on the projection screens and in love with the quality of the sound and how the bass hit you in the chest. As I was sitting there I realized how loud it was in the arena and I began to wonder how loud it really was. Of course I took out my iPhone that has a decibel reader and measured it to be around 103 dB with peaks around 106-108 dB. It’s surprising to me how accurate these little apps actually are.
I wondered if the sound levels could be damaging to people’s ears and how long could someone listen to music at this level before this damage would happen. To find this out we must learn how sound is measured.
How is sound measured?
According to Wikipedia a decibel is a logarithmic unit used to express the ratio of two values of a physical quantity, often power or intensity. In other words, it’s a unit used to measure the intensity of sound. There are three common filters of measuring a decibel, dB(A), dB(B), and dB(C).
A-weighted is the standard weighting of audible frequencies which are designed to mimic the response of a human ear. Therefore, frequencies that are too low for the human ear are filtered out. This is the most common.
dB(B) and dB(C)
B-weight is suitable for frequencies that are at very high levels and sits between db(A) and dB(C). Both of these filters are seldom used.
Sound pressure is the force of sound on a surface area perpendicular to the direction of the sound.
What is too loud?
This has been a very common issue inside the church. It has been debated by our church staff and elders for years. Almost monthly there seems to be someone who has the issue of the music being too loud. The typical conversation usually involves the person either complaining directly to me or a pastor or someone else on staff. Most of the time the person complaining doesn’t actually know why it’s too loud for them. I usually ask questions like, what sound do you hear bothers you? Is it the high pitch frequencies of the cymbals? Guitars? Or is it the lower frequency sounds of the bass guitar or kick drum? Many times their answer is just, it’s too loud.
At our church we had a meeting to discuss the sound levels. I had discussed with other churches both with smaller and larger sanctuaries and sound systems and asked them what their levels were at and came up with the most common level being at 90 dB(A) and we realize that at times levels will peak higher but shall average at that level. According to OSHA sound levels at this level can be experienced for up to 8 hours a day without doing any damage to the ears. Here is an OSHA chart on sound levels:
As you can see keeping the levels lower is the best option. According to the chart I would have been able to experience the concert between one and two hours. We did get a break between the artists and speakers but overall the concert lasted 4 and a half hours.
So, what is your next step is properly measuring sound in your church? I highly recommend getting a sound meter like this one:
They aren’t very expensive and are very useful tools
Make sure that sound meter is set to dB(A). Remember that the lower frequencies are filtered out. Most of the time these lower frequencies are felt rather than heard and usually don’t bother anyone as much as the higher frequencies and then set the response to slow.
Remember that a level of 90 dB(A) isn’t going to always be the magical number. Adjust accordingly and remember that if your mix isn’t balanced it could feel painful even if the sound levels are low. If you are having issues with the mix I would suggest learning more about mixing properly.
Always, keep the meter handy and keep consistent in measuring the levels during your weekend services to make sure you keep within the range that you want to keep your sound in. I would also recommend logging your data so you can show pastors and leaders and hold yourself accountable.