Volume 8 Issue 3 (pdf) - Andrew John Publishing Inc
Volume 8 Issue 3 (pdf) - Andrew John Publishing Inc
Volume 8 Issue 3 (pdf) - Andrew John Publishing Inc
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Figure 2. The noise level inside the headset.<br />
Figure 3. Set-up for the experiment.<br />
cups. Usually, the user adjusts the signal<br />
to a comfortable listening level for speech<br />
or music.<br />
Can the use of headsets<br />
daMage our ears<br />
How much does the level of the signal<br />
have to be raised above the background<br />
noise to ensure comfortable<br />
intelligibility At Ryerson University, 22<br />
students were individually presented<br />
with a speech signal (non-related<br />
sentences) through a headset. They were<br />
asked to adjust the level to be able to<br />
understand it properly. Three different<br />
types of background noise – babbling<br />
speech, industrial noise and construction<br />
noise – were introduced in a soundtreated<br />
room where the tests were<br />
performed. Two headsets were used: one<br />
with high attenuation and one with low<br />
attenuation.<br />
For the low attenuation headset (average<br />
measured attenuation 0.7 dBA), our<br />
results show that the addition of the<br />
speech signal increased the sound level<br />
by as much as 5 dBA. For example, if the<br />
background noise level is 85 dBA, the<br />
level inside the headset could be as high<br />
as 90 dBA (background noise + speech<br />
signal).<br />
The high attenuation headset used in our<br />
experiment reduced the background<br />
noise level by an average of 13.5 dBA.<br />
Therefore, a background noise level of 85<br />
dBA would be reduced to 71.5 dBA.<br />
<strong>Inc</strong>luding the speech signal the total<br />
sound level inside the headset would be<br />
76.5 dBA (that is, the background noise<br />
attenuated by the headset, plus the 5 dBA<br />
increase due to speech).<br />
It was found that the resulting sound<br />
levels in the headset are strongly<br />
dependant on the type of background<br />
noise, since different noise spectra mask<br />
speech differently.<br />
The results clearly show that if a person<br />
has to wear a headset in the presence of<br />
noise, he has to make use of a high<br />
attenuation headset to avoid high noise<br />
levels. This way, the associated risk of<br />
hearing loss is greatly reduced.<br />
The three main conclusions of the study<br />
are:<br />
1. In high noise environments,<br />
headsets must be of the high<br />
attenuation type.<br />
2. The increase in noise exposure due<br />
to the signal is on the order of 5 dBA<br />
on top of the background noise<br />
attenuated by the headset.<br />
3. This increase is highly dependent of<br />
the type of noise in the environment<br />
(speech, industrial, construction,<br />
etc.).<br />
Canadian Hearing Report 2012;8(3):28-29.<br />
REVUE CANADIENNE D’AUDITION | CANADIAN HEARING REPORT 29
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