The Effect of Speech Presentation Level on Acceptance of Background Noise in Listeners with Normal Hearing

Abstract

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.

Acceptable noise level with Danish, Swedish, and non-semantic speech materials

“…This is a finding similar to previously reported. Again, we found SDs for ANL between 6.9 dB and 10.2 dB also depending on study population and test condition, which is similar to SDs previously reported that ranged between 1.7 and 11.0 dB for normalhearing subjects (Nabelek et al, 1991;Rogers et al, 2003;Franklin et al, 2006;Freyaldenhoven et al, 2006;von Hapsburg & Bahng, 2006;Freyaldenhoven et al, 2007). Furthermore, as in previous studies (Nabelek et al, 1991;Rogers et al, 2003), we found no associations between ANL and age or PTA.…”

“…This suggests that the magnitude of ANL is linked to unexplored auditory functions as expressed through electrophysiological responses. However, the indication, that examiner attitude, instructions and/or cultural differences have affected the present results, could provide at least a partial explanation for the individual differences in ANL seen in normal-hearing subjects and the quite large differences in average ANLs seen between previous studies using the same speech materials (Nabelek et al, 1991;Rogers et al, 2003;Harkrider & Smith, 2005;Franklin et al, 2006;von Hapsburg & Bahng, 2006;Freyaldenhoven et al, 2007;Gordon-Hickey & Moore, 2007;Plyler et al, 2008).…”

“…Furthermore, there are no significant differences in MCL between the two populations which might be expected if there were large enough differences between the speech signals. Previous studies have also shown that the BNL decreases and ANL increases with increasing MCL (Franklin et al, 2006; and there is also a difference in initial stimulus level between the Danish and Swedish parts of the study that could also have affected the results. Again, since we recorded no differences in MCL levels across countries, these are perhaps less probable causes of the ANL differences seen.…”

“…Nabelek et al, 1991;Nabelek et al, 2004;Freyaldenhoven et al, 2006). ANL has been established within the range 1-28 dB in normal hearing subjects using mainly an American speech material and different types of noise signals (Nabelek et al, 1991;Rogers et al, 2003;Franklin et al, 2006;Freyaldenhoven et al, 2006;von Hapsburg & Bahng, 2006;Freyaldenhoven et al, 2007;Gordon-Hickey & Moore, 2007;Plyler et al, 2008), but no plausible explanation for this variation has been provided yet (Nabelek et al, 1991;Rogers et al, 2003;Nabelek et al, 2004;Harkrider & Smith, 2005;Freyaldenhoven et al, 2006;Gordon-Hickey & Moore, 2007).…”

Acceptable noise level: Repeatability with Danish and non-semantic speech materials for adults with normal hearing

“…In eight ANL studies with normal subjects (Nabelek et al, 1991;Rogers et al, 2003;Franklin et al, 2006;Freyaldenhoven et al, 2006;Tampas and Harkrider, 2006;von Hapsburg and Bahng, 2006;Freyaldenhoven et al, 2007) a wide range of inter-individual SD's were reported. The median interindividual SD across the studies was 5.3 dB (range: 1.8-11.0).…”