A method has been established to measure the maximum acceptable background noise level
(BNL) for a listener, while listening to speech at the most comfortable listening
level (MCL). The acceptable noise level (ANL) is the difference between BNL and MCL.
In the present study, the ANL procedure was used to measure acceptance of noise, first,
in the presence of speech at MCL and, then, for speech presented at much lower and
higher levels in listeners with normal hearing. This study used the term ANL to describe
the results obtained at MCL and also at other speech presentation levels. The mean
ANL at MCL was 15.5 dB, which is comparable to results obtained by previous investigators.
ANL increases systematically with speech presentation level. Mean ANLs ranged from
10.6 dB when speech was presented at 20 dB HL to 24.6 dB when speech was presented
at 76 dB HL. The results indicated that the acceptance of noise depends significantly
on speech presentation level.
Key Words
Acceptable noise level - background noise level - most comfortable listening level
- signal-to-noise ratio
