SOAE bouncing occurs in an open meatus, not only in a sealed ear canal

Evidence

Here, we recorded SOAEs in the open meatus using an ER10C probe microphone fitted to the meatus via an about 8 cm silicon tube (2.8 mm outer diameter) which did not block the meatus. The tip of the tube was positioned about 10 mm in front of the tympanum. LF exposure was provided by two powerful custom-made subwoofers. Subjects lay on a deck chair in a long basement corridor at a point where standing waves in the corridor maximised the sound level at 30 Hz. LF exposure was 118 dB SPL for 90 s. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3703

Categorization

• QUESTION: Rules out middle-ear impedance change as the mechanism, leaving cochlear homeostasis as the explanation — but was there a self-calibration concern about probe placement affecting measured levels?