Parallel smooth surfaces generate rapid flutter echoes as energy bounces between them
Evidence
The second major acoustical defect in reverberant decay occurs when there are two precisely parallel and smooth surfaces, as shown in Figure 6.16. This results in a series of rapidly spaced echoes, onomatopoeically called flutter echoes, which result as the energy shuttles backward and forward between the two surfaces. These are most easily detected by clapping one’s hands between the parallel surfaces to provide the packet of sound energy to excite the flutter echo. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1871
The second major acoustical defect in reverberant decay occurs when there are two precisely parallel and smooth surfaces, as shown in Figure 6.16. This results in a series of rapidly spaced echoes, onomatopoeically called flutter echoes, which result as the energy shuttles backward and forward between the two surfaces. These are most easily detected by clapping one’s hands between the parallel surfaces to provide the packet of sound energy to excite the flutter echo. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1871
Categorization
- DEFINE: Defines flutter echo and its physical mechanism of energy shuttling between parallel surfaces, with a simple clap test to detect it.
- SHARE: Good to share with anyone who works in acoustics or records audio in rooms — the hand-clap test is a practical trick.
- STORYSTEM: A character who can diagnose any room by clapping once — reading a building’s secret parallel walls like a pulse.
- corroborated: 4 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1871
- XREF: connects to: Nearby reflecting surfaces constructively pile up wave reflections to amplify sound