Effectiveness of narrow-band versus tonal off-frequency maskers.
Résumé
The present study was a follow-up to a pilot study in which it was found that a 500-Hz-wide
narrow-band noise ~NBN! masker produced more masking than a tonal ~T! masker for signal
frequencies both above and below the masker frequency. The aim of the present study was to
determine to what extent these results were influenced by an interaction of the relatively rapid
temporal envelope fluctuations of the NBN and the short ~10-ms! duration of the signal. In the first
experiment, the masking produced by a regular NBN, a low-noise noise ~LNN!, and a T was
compared. The LNN produced less masking than the NBN, and about as much as the T, suggesting
that the inherent amplitude fluctuations in the NBN were largely responsible for the greater masking
produced by that masker. In the second experiment, the masking produced by a regular NBN was
compared with that by a T for a signal duration of 10 or 200 ms. The difference in masking between
the two maskers was reduced or eliminated when the signal duration was 200 ms, because the
threshold in the presence of the NBN masker decreased more with increasing signal duration. This
could reflect a decreased ‘‘confusion’’ between the signal and the inherent fluctuations of the NBN
masker.