Question

The volume of an auditorium is 12,000m³. Its reverberation time is 1.61 seconds. If the average absorption coefficient of interior surfaces is 0.4 Sabine/m². Find the area of interior surfaces.

1. 20,000 m²
2. 3000 m²
3. 450 m²
4. 4500 m²

Answer 1

Correct Answer - Option 2 : 3000 m²

\(R{T_{60}}\; = \;\frac{{0.161V}}{{Sa}}\)

Where RT₆₀ is the reverberation time (to drop 60 dB), V is the volume of the room (m³), S is the total surface area of the room (m²), a is the average absorption coefficient of room surface (Sabine/m²) and Sa is the total absorption in sabines.

\(1.61\; = \;0.161 \times \frac{{12000}}{{0.4 \times S}} \Rightarrow S\; = \;3000\;{m^2}\)