Accession Number:

ADA214169

Title:

Effect of Contralateral Masking Parameters on Difference Limen for Intensity

Descriptive Note:

Final rept.

Corporate Author:

HUMAN ENGINEERING LAB ABERDEEN PROVING GROUND MD

Personal Author(s):

Report Date:

1989-09-01

Pagination or Media Count:

82.0

Abstract:

This study investigated the effect of narrow band and wide band contralateral masking using different overall sound pressure levels SPL on a difference limen threshold for intensity task. Specifically, the narrow band of masking was created by passing white noise through a 110 octave filter. The wide band of masking was created by passing this noise through a 13 octave filter. The results of the study indicated that 1. Contralateral masking influenced a subjects ability to detect small changes in intensity. 2. These masking effects did not change significantly p.05 from Day 1 to Day 2 of the experiment. 3. When the overall SPL was changed by 6 dB and the bandwidth held constant at either 277 or 926 Hz, no significant difference was discovered in the ability to detect small incremental intensity changes. 4. When the masking bandwidth were varied and the overall SPL was held constant, a significant difference occurred. The wide band masking conditions were all more sensitive than the narrow bandwidths with the same SPL. 5. When the bandwidth and the overall SPL of the contralateral masker were varied, a significant difference occurred. 6. The experiment demonstrated that the wide band masker appeared to widen the ipsilateral critical band at 4000 Hz and that this pattern held for the four levels 30, 36, 50, 56 dB of wide band masking presented in the study. jhd

Subject Categories:

  • Human Factors Engineering and Man Machine Systems

Distribution Statement:

APPROVED FOR PUBLIC RELEASE