Building Acoustics

148 Building acoustics

Floor: α = 0.05

Scat. elements: α =0.01

q = 0.025

1.0 23 5 10.0 2030 50100.0

Distance (m)

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

Relative SPL (dB)

Alpha for ceiling

0.10

0.25

0.50

0.75

0.95

Figure 4.23 The relative sound pressure level as a function of distance from a source in a “flat” room. The room
is 5 metres high. The parameter on the curves is the absorption factor α for the ceiling.

Ceiling: α = 0.50

Floor: α = 0.05

Scat. elements: α =0.01

1.0 23 5 10.0 2030 50100.0

Distance (m)

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

Relative SPL (dB)

Scatt. cross section q (m-1)

0.0

0.025

0.05

0.1

Figure 4.24 The relative sound pressure level as a function of distance from a source in a “flat” room. The room
is 5 metres high. The parameter on the curves is the scattering cross section q (m-1).