Conventional distortion metrics cannot predict human response to music or movies

Evidence

The result of this is that traditional measures of harmonic or intermodulation distortion are almost meaningless. They do not quantify distortion in a way that can, with any reliability, predict a human response to it while listening to music or movies. They do not correlate because they ignore any characteristics of the human receptor, itself an outrageously non-linear device. The excessive simplicity of the signals also remains a problem. Music and movies offer an infinite variety of input signals and therefore an infinite variety of distorted outputs. The only meaningful target for conventional distortion metrics is “zero.” Above that, somebody, sometime, listening to something, may be aware of distortion, but we cannot define it in advance. — , Toole, Floyd E - Sound reproduction-…, 458

The end result of this is that traditional measures of harmonic or intermodulation distortion are flawed. They do not quantify distortion in a way that can, with any reliability, predict a human response to it while listening to music or movies. They do not correlate because they ignore any characteristics of the human listener, itself an outrageously non-linear device. The excessive simplicity of the signals also remains a problem. Music and movies offer an infinite variety of input signals and therefore an infinite variety of distorted outputs. The only meaningful target for conventional distortion metrics is “zero”. Above that somebody, sometime, listening to something, may be aware of distortion, but we cannot define it in advance. — Toole, Floyd E, Sound reproduction- the acoustics and…, 991

Categorization

• DEEPTHINKING: The claim that the only meaningful distortion target is zero — because the listener is itself an outrageously nonlinear device — upends the entire engineering measurement paradigm and resists easy summary.
• SEED: Potential piece: ‘Why your distortion specs are lying to you’ — the argument that measurement culture measures devices in ways that ignore the far more nonlinear human receptor.
• XREF: Connects to the reader’s broader interest in why technical audio measurements (THD, IMD) so often fail to predict listener preferences — a recurring theme in loudspeaker reviews and subjective vs. objective debates. — connects to: Traditional distortion specs fail to predict perceived sound quality; Science cannot measure the aesthetic qualities that make music revered — , Toole, Floyd E - Sound reproduction-…, 41; Distortion rarely drives subjective ratings of consumer loudspeakers (+5 more)
• corroborated: 2 independent passages support this claim — , Toole, Floyd E - Sound reproduction-…, 458; Toole, Floyd E, Sound reproduction- the acoustics and…, 991

Broader Connections

• Distortion rarely drives subjective ratings of consumer loudspeakers #exemplifies (0.95)
• Objective sound quality models have limited domains of validity and cannot replace subjective testing #corroborates (0.95) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2337
• Headphone test-fixture measurements often fail to predict what individual listeners hear #exemplifies (0.90)
• Sound reproduction’s endpoint is the human listener, not fidelity per se #expands (0.90)
• Sound power alone cannot predict listener preference for loudspeakers #corroborates (0.85) — Toole, Floyd E, Sound reproduction- the acoustics and…, 1204
• Visual and contextual cues bias human judgments of sound quality #expands (0.80)