| Regardless of the source, all sound waves exhibit | | | | sound energy produced reflects quickly back to |
| certain characteristics when they change | | | | your ears. Due to the human ear’s inability to |
| mediums. Sound waves are actually vibrations | | | | distinguish sound signals as recurrent as 0.1 |
| which travel from molecule to molecule through | | | | seconds apart, reverberations are interpreted as |
| most substances. For instance, sound waves can | | | | one lingering sound. |
| easily travel through means such as air, water, | | | | Now suppose you are standing in a giant canyon, |
| drywall, metal and concrete, an inherent capability | | | | enclosed by walls one hundred feet away on |
| that presents the primary challenge in many | | | | either side, and you yell your name with the same |
| sound reduction and soundproofing endeavors. | | | | intensity as you did in the small room. The longer |
| If you are in an enclosed room and yell your | | | | distance to the walls of the canyon causes sound |
| name, a portion of the sound waves you create | | | | energy to take longer to reflect off of a wall and |
| will attempt to pass through molecules of the | | | | return to your ear. With a lapse greater than 0.1 |
| walls, ceiling and floor of the room, while the | | | | second passing before the reflected sound energy |
| balance of the wave reflects from these surfaces | | | | once again reaches your ear, you are able to |
| and remains within the room. Sound transmission | | | | interpret two separate sound signals, a scenario |
| refers to the passing of a portion of the energy | | | | which exemplifies the defining characteristics of an |
| through the surfaces enclosing the room, while | | | | echo. |
| sound reflection refers to the behavior of the | | | | The time it takes for a reverberation to weaken |
| energy which reflects and remains within the | | | | by 60 or more decibels and become inaudible is a |
| room. | | | | metric known as reverberation time (RT). Each |
| Sound reflection, or the sound energy that | | | | room has a fixed RT value, which is influenced by |
| reflected back into the room as you yelled your | | | | such variables as the size and shape of the room, |
| name, can be further classified by a | | | | characteristics of the surface textures and the |
| measurement of the time lapse between the end | | | | intensity of the original sound energy. With |
| of the sound’s introduction and its reentry | | | | reverberations lasting more than 1.5 – 2 |
| back into the room. Signals with such a time lapse | | | | seconds, the human ear can no longer accurately |
| lasting less than 0.1 second are reverberations, | | | | interpret individual sounds, and background noise |
| while signals exhibiting a time lapse greater than | | | | becomes an issue. For this reason, targeting the |
| 0.1 second constitute echoes. To understand the | | | | capture of sound reflections, eliminating |
| distinction between reverberations and echoes, | | | | background noise and maintaining RT values below |
| imagine once again yelling your name within an | | | | two seconds are common goals across many |
| enclosed room. Since you are in close proximity | | | | sound reduction and soundproofing projects. |
| to the walls, ceiling and floor of the room, the | | | | |