I now use acoustical modeling for nearly all room acoustics calculations. In the left column are graphics from a model that I used to calculate the reduction in sound-level resulting from adding sound-absorbing surfaces to a band rehearsal room. Sound levels are indicated by colors, which decrease with distance from the source.

A legend on the right in both graphics shows the sound levels represented by the colors. The change from pink to red in the farther reaches of the room indicates a reduction of 5dB (@ 2,000 Hz) from 102 dB to 97 dB. Note that there is no reduction at all in the immediate vicinity of the source. The model provides a clear illustration of the benefits---and limitations---of sound level reduction through the use of sound-absorbing room surfaces.