WOLFRAM|DEMONSTRATIONS PROJECT

Logarithmic Scales in Acoustic Spectra: Decibels and Octaves

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plot type
ListPlot
ListLogPlot
ListLogLinearPlot
ListLogLogPlot
waveform
sawtooth
square
wave 1
wave 2
wave 3
spectrum
amplitude
power
show hertz
show magnitude
show octaves
show decibels
show waveform
show function
play sound
In acoustics, huge changes in measurable physical parameters (pressure, power, frequency) correspond to relatively small changes in perceived properties (loudness, pitch). Simply using a linear scale is impractical, since the variation gives an inadequate guide to the perceived sound. Instead it is more practical to convert to logarithmic scales. Octaves are the logarithmic units for frequency, and decibels are the logarithmic units for pressure and power. Use this Demonstration to see the relationship between linear and logarithmic units in the spectra of different acoustic waveforms.