Building Acoustics deals with sound propagation between rooms. Typically, to unwanted sound, i.e. when you want to hear as little as possible of what is going on in adjacent rooms.
General
Building Acoustics deals with sound propagation between rooms. Typically, to unwanted sound, i.e. when you want to hear as little as possible of what is going on in adjacent rooms.
In building acoustics where we concentrate on the noise level due to what goes on in adjacent rooms (or outside) an important parameter is the sound insulation.
Values in building acoustics should be normalised and objective, i.e. independent of the current conditions (amount of absorption) of the room.
We are here talking about the source room â which is where the noise originates â and the receiving room â where we measure the amount of noise coming through the wall.
By correcting the measured level difference in a certain way, we compensate for the effect that the reverberation time has on the sound level in the receiving room.
Level difference D
D = L1 - L2
where
L1 is the energy-average sound pressure level in the source room, which contains the loudspeaker.
L2 is the energy-average sound pressure level in the receiving room.
Standardized level difference DnT
DnT = D + 10lg(T / T0)
where
T is the reverberation time in the receiving room.
T0 is the reference reverberation time; for dwellings, T0 = 0.5 s.
Apparent sound reduction index R'
R' = D + 10lg(S / A)
where
S is the area of the common partition.
A is the equivalent absorption area of the receiving room.
Equivalent absorption area A
A = 0.16 V / T
where
V is the receiving room volume.
T is the reverberation time in the receiving room.
Standardized impact sound pressure level L'nT
L'nT = Li - 10lg(T / T0)
where
Li is the energy-average impact sound pressure level in the receiving room, where the impact source is the tapping machine.
T is the reverberation time in the receiving room.
T0 is the reference reverberation time; for dwellings, T0 = 0.5 s.
Normalized impact sound pressure level L'n
L'n = Li + 10lg(A / A0)
where
Li is the energy-average impact sound pressure level in the receiving room, where the impact source is the tapping machine.
A is the equivalent absorption area of the receiving room.
A0 is the reference absorption area; for dwellings, A0 = 10 m2.