A room has dimensions of 4 x 6 x 3 m high. The walls are made by plywood paneling, the floor is covered with carpet on the concrete slab and the ceiling is perforated acoustic tile on a furring backing. There are 2 windows of ordinary glass, each 1.5 x 1 m, and the windows are closed. An electric motor (directivity factor, Q = 2.5) located in the room has a sound power level of 90 dB. Determine the steady-state sound pressure level at a distance of 2 m from the motor. Take the sound absorption coefficients as 0.20 for carpet, 0.18 for plywood panel, 0.04 for window, 0.55 for acoustic tile.

A room has dimensions of 4 x 6 x 3 m high. The walls are made by plywood paneling, the floor is covered with carpet on the concrete slab and the ceiling is perforated acoustic tile on a furring backing. There are 2 windows of ordinary glass, each 1.5 x 1 m, and the windows are closed. An electric motor (directivity factor, Q = 2.5) located in the room has a sound power level of 90 dB. Determine the steady-state sound pressure level at a distance of 2 m from the motor. Take the sound absorption coefficients as 0.20 for carpet, 0.18 for plywood panel, 0.04 for window, 0.55 for acoustic tile.