Each basilar membrane location acts as a bandpass filter tuned to a center frequency

Evidence

The action of the basilar membrane can be thought of as being equivalent to a large number of overlapping band-pass filters, or a “bank” of band-pass filters, each responding to a particular band of frequencies (see Chapter 1). Based on the idealized filter response curve shape in Figure 2.10(a), an illustration of the nature of this bank of filters is given in Figure 2.10(b). Each filter has an asymmetric shape to its response, with a steeper roll-off on the high-frequency side than on the lowfrequency side; the bandwidth of a particular filter is given by the critical bandwidth (see Figure 2.8) for any particular center frequency. It is not possible to be particularly exact with regard to the extent to which the filters overlap. A common practical compromise, for example, in studio third octave graphic equalizer filter banks, is to overlap adjacent filters at the −3 dB points on their response curves. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 595

Categorization

• DEFINE: Clarifies the core psychoacoustic model of the basilar membrane as a filter bank, and defines the practical −3 dB overlap convention used in graphic equalizers.
• XREF: This filter-bank model of the cochlea connects to how graphic equalizers and critical bandwidths are implemented; links conceptually to earlier chapters’ treatment of filters and to later material on masking and critical bands. — connects to: Frequency sorting in the basilar membrane can be reproduced in physical models; Broad-spectrum sounds read as louder because auditory bands integrate across the basilar membrane; Efferent stimulation maximally suppresses basilar membrane vibration near the characteristic frequency (+9 more)
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 595

Broader Connections

• Auditory filters respond asymmetrically, favoring frequencies below center #expands (0.88) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1124
• Basilar membrane displacement produces an asymmetric filter response across frequency. #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 593
• Auditory filter bandwidth scales nonlinearly with center frequency #expands (0.82)
• Just-noticeable frequency shifts map to constant basilar distances #expands (0.75) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 929
• Loudness growth mirrors basilar membrane input-output functions #qualifies (0.72)