The ER-10B+ Low Noise™ DPOAE Microphone has a flat frequency response through 10 kHz, with a noise level 10 dB below that of the human ear. Battery operation prevents ground loop problems. Requires external sound source: wide band earphones (ER-2) or high output earphones (ER-3C). Earphones are sold separately.
keyword : physiology, auditory, etymotic