The ear functions as a bank of frequency-selective filters tuned to basilar membrane places

Evidence

The response characteristic of an individual filter is illustrated in the bottom curve in Figure 2.8, the vertical axis of which is marked “filter response” (notice that increasing frequency is plotted from right to left in this figure in keeping with Figure 2.5 relating to basilar membrane dis­ placement). The other curves in the figure are idealized envelopes of basilar membrane displacement for pure tone inputs spaced by f Hz, where f is the distance between each vertical line as marked. The filter center frequency Fc Hz is indicated with an unbroken vertical line, which also represents the place on the basilar membrane corresponding to a frequency Fc Hz. The filter response curve is plotted by observing the basilar membrane displace­ ment at the place corresponding to Fc Hz for each input pure tone and plotting this as the filter response at the frequency of the pure tone. — David Howard, Jamie Angus, coustics and Psychoacoustics, 573

Categorization

• DEFINE: Defines the core auditory filter concept: measured filter response equals basilar membrane displacement sampled at a fixed place.
• XREF: Relates to the place theory of pitch and classic auditory filter models (Patterson, Moore) the reader may encounter in later chapters.