Sound Waves: Characteristics and Applications · Lesson 12 of 14
Reverberation
“Closely spaced multiple reflections make sound persist in large spaces and must be controlled for clarity.”
• Define reverberation. • Explain how multiple reflections produce persistence of sound. • Distinguish reverberation from a separate echo. • Explain how auditorium materials control reverberation. • Relate architectural design to desirable sound.
Reflected sound does not always arrive as a clearly separated echo. In a large hall, many reflections can return close together and cause sound to continue briefly even after the source stops.
Reverberation
Persistence of sound caused by multiple reflections that continue to reach a listener after the source stops producing sound.
The chapter describes reverberation as occurring when reflected sounds arrive with time differences less than about 0.05 s. Instead of being heard as distinct repetitions, they blend into a continuing sound.
Useful and Unwanted Reverberation
A certain amount of reverberation can help music or speech reach listeners throughout a large auditorium. Too much, however, makes successive sounds overlap and can make speech garbled.
Modern halls use sound-absorbing panels, upholstered seating, curtains and other soft porous surfaces to reduce unwanted reflections. Curved or carefully shaped surfaces can also be used to guide sound more effectively.
The chapter mentions the Whispering Gallery of Gol Gumbaz in Bijapur as an example of architecture with striking acoustic behaviour, where a faint whisper can be heard multiple times across the dome.
An echo is heard as a distinct returned sound after sufficient delay. Reverberation is a persistence created by many reflections arriving too close together to separate.
Quiz
Which description best matches Reverberation?
Which term matches this description: Persistence of sound caused by multiple reflections that continue to reach a listener after the source stops producing sound.
Which statement is a key takeaway from this lesson?
Which additional statement is also a key takeaway from this lesson?
Which further statement is also a key takeaway from this lesson?
Practice Problems
- Define reverberation.
- Why can too much reverberation make speech difficult to understand?
- List materials that can reduce unwanted reverberation.
- Explain the difference between echo and reverberation.
Key Takeaways
• Reverberation is the persistence of sound caused by repeated reflections from surfaces. • Unlike a clear echo, the reflected sounds arrive so close together that they overlap with the original sound. • Excessive reverberation can reduce speech and music clarity. • Soft and sound-absorbing materials can be used to control reverberation in halls and auditoriums.