period three
Acoustical Analysis
notes
Sound Transmission
W | absorbed |
Wa sound energy | |
i |
|
incident |
|
sound energy | Wt |
| |
| transmitted |
| sound energy |
Wr |
|
reflected |
|
sound energy | Figure 47 |
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The total sound energy that strikes a surface (Wi) is either reflected (Wr), absorbed by the material (Wa), or transmitted through the material (Wt).
A material provides a barrier to the incident sound energy (Wi) when it reduces the amount of sound energy that is transmitted through the material (Wt). There are a number of factors that affect the amount of sound transmitted through the wall, including the type and thickness of material, frequency of the sound, and quality of construction.
Materials that are dense (such as masonry block or wallboard) or stiff (such as glass) are generally better at reducing transmitted sound than materials that are lightweight or flexible. Increasing the thickness of a material reduces the amount of sound transmitted through it. Finally, the ability of a material to reduce transmitted sound depends on frequency.
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