Temporary threshold shifts after onset and offset of moderately loud low-frequency maskers

Moderately loud low-frequency maskers produce temporary threshold shifts which oscillate for a few minutes in reproducible patterns not only after their offset, but also after their onset. The temporal variations of threshold show "bounces" similar to those found by Hirsh and Ward [J. Acoust. Soc. Am. 24, 131-141 (1952)] after the offset of very loud maskers. In the present paper, threshold shifts of up to 30 dB are reported for pauses of 3-min duration in continuous maskers. These effects could originate in the internal cochlear metabolism, the steady-state condition of which seems to be influenced by the moderately loud low-frequency tones.