BIEB 166 Lecture Notes - Lecture 17: Sound, Acoustic Impedance, Scattered Disc
8 Nov 2013
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Document Summary
Frequency domain sources of signal distortion during propagation. When sound is being produced, it is spreading out to the environment. Even there is nothing blocking the sound, the sound will decrease in loudness as it travel further from the sound source. In air, lose 6db in pressure per doubling of distance. Different objects that are absorbing sound in the environment. Shows three different spectra on top of each other. Furthering away from the sound source, more attenuation. In each of the individual spectra, there is a peak at the same frequency (2khz) Frequencies that are not 2khz are being absorbed more than the 2khz frequency. This illustrates a characteristic of resonance (resonance is at around 2khz) The high frequencies, they are absorbed more rapidly. The animal would prefer to communicate at 2khz. The kind of scattering depends upon the relative size of the wavelengths of the propagating sound, and that of scattering objects.
