An Acoustical Analysis of the Frequency-Attenuation Response of Musician Earplugs Page: 4
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Citation: Chesky K, Amlani AM (2015) An Acoustical Analysis of the Frequency-Attenuation Response of Musician Earplugs. Commun Disord
Deaf Stud Hearing Aids 3: 127. doi:10.4172/2375-4427.1000127
Page 4 of 5
As shown in Table 1, the mean attenuation levels across the nine
presentation levels for the ER-9 and the ER-15 were significantly
higher (p<0.01) than published rates by about 3.5 dB and 1 dB
respectfully. The ER-25 and the ER-20 attenuation levels across the
nine presentation levels were statistically lower (p<0.01) than
published levels. The mean attenuation level across the nine
presentation levels for the ER-20 was 4.8 dB, much lower than the
reported 12 dB NRR level and markedly lower than the manufacturer-
claimed 20 dB of attenuation for an earplug inserted correctly.
MEP dB t df Sig Mean 95% CI
Type Mean (SD)Difference Lower Upper
ER-9 12.7718 (. 14.226 8 .000 3.7718 3.1604 4.3832
ER-15 16.1757 (. 7.477 8 .000 1.1757 .8131 1.5384
ER-25 23.4805 (. -6.242 8 .000 -1.5195 -2.0809 -.9582
ER-20 4.8658 (. -102.36 8 .000 -15.1342 -15.4752 -14.793
Table 1: Statistical comparisons based on one sample t-test.
Figure 5 shows the influence of each MEP condition on the spectral
characteristics of the music stimuli by graphically contrasting the
unoccluded condition to the occluded conditions at the 97 dB
The resultant attenuation curves for each of the 4 MEP conditions,
derived from graphing the differences between the unoccluded and the
occluded conditions, are shown in Figure 6. Here, the data clearly
show that the MEPs do not reduce music equally across frequency.
No plug I ER-9
No plug / ER-15
:1 i__ _ _ _ S te ____
No plug / ER-20
No plug/ ER-25
Figure 5: Frequency responses of MEPs compared to no plug condition as measured in KEMAR at 97 dB presentation level.
................ . .... ...
.. .. . .. . .. . .. . .. .
Figure 6: Attenuation responses for MEPs.
Our objective measurements inside ear of KEMAR confirm that the
spectral characteristics of music are altered by MEPs, regardless of
whether the earplug was non-custom or custom earplug. Thus, MEPs
do not attenuate musical stimuli in a way that reduces levels equally
across frequencies. These results help explain why musicians 1)
complain that the ER-15 distorts the timbre of music , 2) report the
most important factor for non-use is sonority of their own instrument
, 3) don't like the ER-15 because they change the natural sound of
the instrument , and 4) can't communicate musically when using
the ER-20 . This also offers an important hypothesis regarding
why the spectral characteristics of musical output changes when
musicians use and perform using ER-15 earplugs .
Commun Disord Deaf Stud Hearing Aids
ISSN:2375-4427 JCDSHA, an open access journal
Volume 3 . Issue 1 . 1000127
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Chesky, Kris S. & Amlani, Amyn M. An Acoustical Analysis of the Frequency-Attenuation Response of Musician Earplugs, article, January 16, 2015; Los Angeles, California. (https://digital.library.unt.edu/ark:/67531/metadc1042574/m1/4/: accessed June 14, 2021), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT College of Music.