Ray Deck on using a dB meter:
At some point, every pastor will face criticism about music volume. A few preemptive steps will go a long way to prepare you for the inevitable noise complaint.
Noise complaints are usually subjective, made on feeling or impression. It’s important to measure the sound in the auditorium for both frequency and overall volume so you can respond with a scientific measurement.
The metric used to measure volume is called a decibel (dB). Some common benchmarks are:
0 dB: rustling leaves
60 dB: conversation
85 dB: city traffic
100 dB: stock earphones at maximum volume
120 dB: a clap of thunder
You can buy a meter to wire directly into your soundboard, but I prefer to use a free Android app called Noise Meter. (iOS users, what’s your favorite equivalent?)