Bone vibrator placement and the cancellation technique.
An issue in the measurement of bone conduction sensitivity is the placement of the bone vibrator. The effect of bone vibrator position on the amplitude and phase of the received signal was investigated using a cancellation technique. This technique involves cancelling the signal delivered by the bone vibrator with a signal delivered acoustically via an earphone. At cancellation, the acoustic signal is equal in amplitude but opposite in phase to the bone-conducted signal. Results showed that the amplitude of the received signal did not vary significantly with bone vibrator position close to the center of the forehead whereas the phase of the received signal was critically dependent on bone vibrator position. Substantial intersubject differences were observed in the variation of phase with bone vibrator position. The precision of measurement using the cancellation technique was found to be high.
Department of Speech, Communication Sciences & Theater, St. John's University, Jamaica, New York.
J J
JJ
Dempsey
H
H
Levitt
D000162:Acoustics / Q000295:instrumentation*; D001844:Bone Conduction; D003051:Cochlea / Q000502:physiology; D005546:Forehead; D006801:Humans; D008416:Mastoid; D014732:Vibration