Modern worship centers often have a semi-circle, auditorium-like design, as mentioned in Acoustical Design for Contemporary Churches. This design proves to be much more acoustically friendly, yet tends to hold “dead spots” in odd locations.
Grace Polaris’s sound engineer, Brent Dye, had a lot to say about the acoustic challenges they faced pre-renovation. “My biggest issue was just with some of the slap back and flutter echoes within the room. You would sit in various corners of the room and it was very difficult to understand what was being said. Intelligibility was just not the best.” Slapback, flutter echoes, and speech intelligibility—oh my! But what exactly does that mean? Essentially, the acoustics were terrible, but here’s the longer explanation:
Slapback is defined by yourdictionary.com as “A kind of doubling echo with relatively long delay between repetitions of the sound, so that the individual echoes can be perceived,”² and Acoustic Sciences Corporation defines flutter echoes as being “produced by sound traveling quickly between two parallel reflective surfaces.”³ This both disrupts speech and drastically lowers the quality of music within the space.
As Dye hinted, speech intelligibility is how well one is able to comprehend what the speaker is saying. When echoes and reverberation get too bad, speech intelligibility suffers a great deal, leaving the audience at a loss. This is critical in a worship center because the pastor’s sermon is the main event during service.