"In order for a microphone to be considered as a high-fidelity component of an audio system, it should produce a transduced signal that faithfully follows the waveform of sound, introducing no distortion of its own. Applying this criterion, the construction and functioning of the ear is extremely poor. [...] The pinna produces resonances and time delays that change the intensity and phase of spectral components in a manner which varies with azimuth and elevation of the source. Although these changes would be considered serious defects if produced by microphones or other physical instruments, they can furnish valuable perceptual information. Thus, the complex acoustic changes produced by the pinnae when a source moves provide information concerning position, and result in perception of an unchanging sound at a changing location. Thus, some spectral changes cannot be perceived as such: they are interpreted as changes occurring in an external physical correlate (azimuth and elevation of the source) while the nature of the sound (its quality or timbre) appears to be unchanged. [...] As Helmholtz has stated: we are exceedingly well trained in finding out by our sensations the objective nature of the objects around us, but we are completely unskilled in observing the sensations per se."

— Auditory Perception by Richard M. Warren