Sound Perception: The Impact of Reverberation

Hello

 Sound travels through the air in waves. Think of a concert venue as an ocean setting. The stage is a wave break, and the audience is the shoreline. The walls--they're the continental shelf. Walls are what determine the affect of the sound wave. 

 So keeping this "ocean of sound" in mind, we can look at how sound is perceived from the audience's point of view. Let's use a teacher giving a speech in a high school gym as an example. The gym is fairly large, often with a maximum occupancy of over 2,000 persons. With this much space, sound is bouncing off of everything and travelling through large spaces when the building is empty. However, when it's filled with 1,000 people, sound seems to die out. This is why we use amplification. So we give the guy giving a microphone and connect it to a PA system at a reasonable volume. Now, everything is perfect. Sound is distributed evenly, reaches every corner of the building. But every amateur in charge of the PA makes the same mistake--they forget to account for reverberation.

Reverberation (or reverb) is the persistence of sound in a particular space after the original sound is produced. Reverb is what allows sound to persist through the air after is has been absorbed by things in it's path. Natural, or architecturally engineered reverb, is already there. Remember in the gym, when the amateur sound guy forgot to account for reverb? That would be totally fine in the gym, because the gym is designed to allow sound to fly through it when people are inside. When artificial reverb is added to a signal, the sound persists. In the gym, this would be horrific. The words of a speaker wouldn't be decipherable at all. However, in a small venue, where the space is enclosed and filled with people, a reverbless signal would die out when it gets absorbed by people. In this scenario, it's okay to add a bit (or a lot) of artificial reverberation. 

 Reverb is a powerful tool in a sound technician's arsenal. Use it wisely. 

sk