Headphone test-fixture measurements often fail to predict what individual listeners hear

Evidence

Measurements with microphones at ear level should be discouraged because they introduce acoustical interference irregularities that are tempting to equalize, but that are not audible problems to human listeners. Microphones should be elevated well above the seat backs, preferably at varied heights to average out regular patterns of interference. However, all such measurements are reliable at low frequencies. — , Toole, Floyd E - Sound reproduction-…, 1355 (#corroborates, via linked claim)

An alternative goal of sound reproduction is to control the sound field within the loudspeaker set-up. This means that the pressure and velocity waves originating from the virtual sources are to be synthesized as plane waves or as spherical waves. The targeted sound field would then be well defined, and the reproduced sound field can also be simulated, or even measured. Unfortunately, the errors in the synthesis of the sound field between the targeted and reproduced fields do not say much about the perceptual significance of the deviation. Sometimes a small difference in the wave field causes a large perceptual deviation, and a large deviation in the wave field may be perceptually irrelevant in some cases. However, the advantage of this starting point is that the reproduction techniques can be derived mathematically. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1902 (#expands, via linked claim)

Ear level microphones in close proximity to orderly rows of seats, some of which have high backs, generate effects more complex and of wider bandwidth than the well-known seat-dip phenomenon in concert halls. The fact that the cinema sound field is considerably less reflective is a probable factor. It is unlikely that these non-minimum-phase acoustical interference effects can be treated by equalization, if indeed they need correction at all. Two ears and a brain are much more analytical and adaptable than an omnidirectional microphone and analyzer. Once stationary in a chair, listeners usually are unaware of, or attribute innocent spatial descriptors to, measured variations suggesting repugnant interference or comb-filtering phenomena. — , Toole, Floyd E - Sound reproduction-…, 1345 (#corroborates, via linked claim)

Categorization

• XREF: connects to: Earphone frequency response must be measured on real ears, not couplers; Impulse response measurements can misrepresent what listeners actually hear; Ear-level microphone measurements capture artifacts inaudible to human listeners — , Toole, Floyd E - Sound reproduction-…, 1355 (+10 more)

Related

• Impulse response measurements can misrepresent what listeners actually hear (similarity 0.95)
• Earphone frequency response must be measured on real ears, not couplers (similarity 0.93)
• Measured interference at ear level often needs no correction (similarity 0.91)
• Ear-level microphone measurements capture artifacts inaudible to human listeners (similarity 0.90)
• Test fixture fidelity to human measurements remains an open question (similarity 0.85)
• The ‘we can’t measure what we hear’ myth stems from inadequate measurements (similarity 0.85)
• Headphone positioning causes large measurement variation below 500 Hz and above 3 kHz. (similarity 0.84)
• Head and ear variation makes fixture measurements unreliable predictors of listening (similarity 0.84)
• Headphone reproducibility varies strongly with frequency, worse at bass and treble extremes (similarity 0.83)
• Sound reproduction’s endpoint is the human listener, not fidelity per se (similarity 0.83)
• Headphone measurement variability is greatest below 500 Hz and above 3 kHz (similarity 0.83)
• The hearing system is not outmeasurable; inadequate measurements explain apparent gaps (similarity 0.83)
• Headphone measurements vary most between individuals at high frequencies. (similarity 0.82)
• Measurement accuracy on fixtures directly predicts agreement with human listeners (similarity 0.80)
• Seat-caused acoustical interference eludes equalization and often goes unnoticed by listeners (similarity 0.80)

Broader Connections

• Ear-level microphone measurements capture artifacts inaudible to human listeners #corroborates (0.85) — , Toole, Floyd E - Sound reproduction-…, 1355
• Physical accuracy of a sound field does not predict perceived accuracy #expands (0.80) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1902
• Measured interference at ear level often needs no correction #corroborates (0.75) — , Toole, Floyd E - Sound reproduction-…, 1345