Convention Paper
Measurements and Perception of Nonlinear Distortion—Comparing Numbers and Sound Quality
AES Convention 123 · Paper 7174 · October 2007
Abstract
The discrepancy between traditional measures of nonlinear distortion and its perception is commonly recognized.
THD, two-tone and multitone intermodulation and coherence function provide certain objective information about
nonlinear properties of a DUT but they do not use any psychoacoustical principles responsible for distortion
perception. Two approaches to building psychoacoustically-relevant measurement methods are discussed; one
is based on simulation of the hearing system.s response similar to the methods used for assessment of codec.s
sound quality. The other approach is based on several ideas such as distinguishing .low-level. versus .high-level.
nonlinearities, low-order versus high-order nonlinearities, and spectral content of distortion signals that occur
below the spectrum of an undistorted signal versus one that overlaps the signal.s spectrum or occurs above it.
Several auralization examples substantiating this approach are demonstrated.
