Pastor Dave Jordan-Irwin contacted ASC because of a high RT-60
(echo) in the Sanctuary, and a poor speech intelligibility response.
They had already spent a considerable sum installing an electronic
noise control system that didn't work. Typically, an acoustic engineer
calculates total cubic foot volume of the space to determine how
many square feet of absorptive panels need to be installed. The
dilemma here is that the recommended RT-60 for speech is 0.8 seconds.
And the RT-60 for music to sound clear and strong is 1.8 seconds.
The cubic
foot formula can be misleading, however, because of the unique acoustics
of churches, and the desired results. An RT-60 that's too low will
make the Sanctuary sound too dead, while an RT-60 that's too high
will have the congregation gritting their teeth. ASC uses the balloon
burst test to determine RT-60 across a range of frequencies,
which is far more accurate.
The
ASC approach is to use minimal absorption placed in the right places
so that both music and speech sound clear and crisp. The first benefit
is less cost due to less acoustic panels. The second benefit is
a happy congregation that experiences the uplifting inspiration
they came for.
ASC
uses highly efficient and diffusive SoundPlanks to help soften wall
reflections from the praise band. We like to keep them down low
where they're needed. We also panelized the SoundPlanks into four
foot ready-to-install units.