Coupler type 4.3 shifts both low and high frequency headphone readings

Evidence

Fixture 5 (B&K Type 5128) produces measurements that significantly deviate from Fixture 1: there is a 5 dB low-frequency roll-off beginning at about 500 Hz and significantly more output above 3 kHz. The differences can be attributed to differences in the acoustical transfer impedance of the Type 4.3 coupler compared to the Type 3.3, and also leakage effects that tend to be larger on artificial heads compared to flat plates. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1733

Categorization

• DEFINE: Explains the Type 3.3 vs Type 4.3 ear simulator distinction through its measurable consequences.
• XREF: connects to: Headphone measurement variability is greatest below 500 Hz and above 3 kHz — Toole, Floyd E, Sound reproduction- the acoustics and…, 1717; Headphone positioning causes large measurement variation below 500 Hz and above 3 kHz.; Headphone reproducibility varies strongly with frequency, worse at bass and treble extremes (+2 more)
• yield-rescued: below the book’s yield-target cutoff, included anyway for connecting to: Headphone measurement variability is greatest below 500 Hz and above 3 kHz — Toole, Floyd E, Sound reproduction- the acoustics and…, 1717; Headphone positioning causes large measurement variation below 500 Hz and above 3 kHz.; Headphone reproducibility varies strongly with frequency, worse at bass and treble extremes (+2 more)

Broader Connections

• Earphone frequency response must be measured on real ears, not couplers #complicates (0.74)