The average human ear is able to detect sounds with frequencies in the 20 Hz range. In order to make sound level measurements over such a wide range feasible, it is usual to perform the analyses by frequency bands with a predefined and standardized width.

In the case of building acoustics, frequency bands between 100 Hz and 5000 Hz are used. The values of the center frequencies and their limits – lower and upper – of the frequency bands used in building acoustics (octaves and thirds of octaves) are shown in the following table: