A tube of a specified length can be used to muffle sounds with frequencies that do not match its resonance frequencies.
Work Step by Step
A tube of a specific length resonates at certain natural frequencies, and sound that is input at or near these frequencies will persist, resonate, and sound relatively loud. On the other hand, input frequencies that are distant from these resonant frequencies are damped out relatively quickly. Thus, the length of the tube can be chosen to muffle certain frequencies.