Search Mathematics of the DFT
Book Index | Global Index
Would you like to be notified by email when Julius Orion Smith III publishes a new entry into his blog?
Audio Decay Time (T60)
In audio, a decay by (one time-constant) is not enough to become inaudible, unless
the starting amplitude was extremely small.
In architectural acoustics (which includes the design of
concert halls ), a more commonly used measure of decay is ``''
(or T60), which is defined as the
time to decay by dB.4.7That is, is obtained by solving the equation
Using the definition of the exponential
, we find
is about seven time constants. See where
Previous: Why Exponentials are ImportantNext: Complex Sinusoids
About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and Associate Professor (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA)
, teaching courses and pursuing research related to signal processing applied to music and audio systems. See http://ccrma.stanford.edu/~jos/