Published on December 31, 2009
Slide 1: PPT on Reflection of sound BY IX-A Slide 2: Contents Echo Reverberation Uses of multiple reflection Slide 3: Echo In audio signal processing and acoustics, an echo is a reflection of sound, arriving at the listener some time after the direct sound. Typical examples are the echo produced by the bottom of a well, by a building, or by the walls of an enclosed room. A true echo is a single reflection of the sound source. To produce an echo the minimum distance should be 17m. To hear the distinct echo the time interval between the original sound and the reflected must be at least 0.1s Slide 4: Reverberation Reverberation is the persistence of sound in a particular space after the original sound is removed. A reverberation, or reverb, is created when a sound is produced in an enclosed space causing a large number of echoes to build up and then slowly decay as the sound is absorbed by the walls and air. This is most noticeable when the sound source stops but the reflections continue, decreasing in amplitude, until they can no longer be heard. Slide 5: Uses of multiple reflection Megaphones or loudhailers, horns, musical instrument, such as trumpets and shehanais, are all designed to send sound in a particular direction without spreading it in all direction. In these instruments, a tube followed by a conical openings reflects sound successively to guide most of the sound waves from the source in the forward direction towards audience. Stethoscope is a medical instrument used for listening to sounds produced within the body. In Stethoscope the sound of the patient’s heartbeat reaches the doctor’s ears buy multiple reflection of sound.