Problem 14.10
A marching band produces sound at the frequencies and sound levels shown
in the table below when the band is 4 m from the listener. When
the band is 128 m from the listener, what sound levels are produced
at the listener's position? Assume that each doubling of the distance
decreases the level by 6 db (Why is this?) Which sounds are audible
if we assume that they become inaudible at the 20-phon level? (This
shows how "band color" might change as a function of distance from
the listener.)
| Frequency (Hz) |
Level at 4 m (dB) |
Level at 128 m (db) |
Audible? |
| 125 |
80 |
- |
- |
| 250 |
70 |
- |
- |
| 500 |
70 |
- |
- |
| 1000 |
60 |
- |
- |
| 4000 |
60 |
- |
- |
| 8000 |
50 |
- |
- |
Solution
David Cinabro
Last modified: Sun Sep 23 22:29:15 EDT 2001