Musicians’ earplugs have flat attenuation

Mead Killion and Andy J. Haapapuro, in the November 2015 issue of Hearing Review have finally put to bed the controversy of whether Musicians’Earplugs have a flat or uniform attenuation.

There have been some publications over the past several years that have questioned the flatness of commercially available musicians’ earplugs.  These publications have contained rather significant errors; some of which actually showed that the musicians’ earplugs were indeed flat, but then concluded that they were not!

So, here is the bottom line: musicians’ earplugs indeed have uniform sound attenuation, as advertised, but depending on how you show the data, different graphical results can be obtained- the same data, just shown differently. When the data are plotted on a log scale for frequency, as is the standard in the hearing health care industry, and indeed, how sound is encoded neurally in the human cochlea, the results are quite flat (from about 80 Hz to 16,000 Hz). There is a small notch in the 8000 Hz region and these data were reported when they first came out in 1988.

There are actually a number of different manufacturers of musicians’ earplugs out there, and even some that are not intended to be used for musicians, but are advertised to be. Like any area of work, beware of what you are getting. If you are a musician reading this blog, be sure to see your local audiologist for their recommendation as well as some strategies to minimize the long term effects of loud music.  Hearing protection is important but certainly not the only thing that can be done to play and listen to music safely.

There are a number of ways to verify musicians’ earplug function in the clinic. Personally I have been fitting them since 1988 when they first came out. Unofficial figures indicate that over 1,000,000 pairs of custom-made musician earplugs have been sold and over 3,000,000 non-custom musician earplugs (such as the ETYPlugs or the newer ER-20XS).  If they didn’t work, they would not have been such a commercial success.

Clinically, it is a simple task to drop a probe microphone in the person’s ear with the earplug in place- the measured real ear attenuation (real ear gain with negative gain) clearly shows that they are flat for each of my clients.  This method need to be done properly and the error some people make is not using a sufficiently high stimulus level for the real ear measurement.  I used 70 dB SPL, but it needs to be high enough such that the stimulus level – attenuation needs to be sufficiently above the noise floor of the real ear measurement device.  Generally a 70 dB stimulus level is fine.

And if you didn’t want to use technology, just fit them on a client and ask them to put their fingers over the air hole and do an A-B-A comparison. When they remove their fingers, and the earplug can function as it was intended, the entire right hand side of a piano comes back.  When my clinic piano is occupied, one can just utter the sound ‘ssss’ as in “silly’, with and without plugging the hole in the musician earplugs, and the ‘s’ is much more audible- the ‘s’ has energy at the very top end of the piano keyboard.

The strength of the musicians’ earplugs (e.g., ER-15) is that they treat all sounds equally- the bass will still sound like the bass; the treble, like the treble. All music is merely reduced from an irritating or damaging level to one that is not, but the shape of the music remains constant.

In the case of the ER-15, all sound is reduced by exactly 15 dB. For those who like to do calculations, for each 3-dB reduction, one can be exposed twice as long with the same damage.  Doing the math a 3-dB reduction is twice as long; another 3 dB (we are down to 6 dB now) is another halving of the damage- down to four times as long; another 3 dB (down to 9 dB now) is 8 times as long; another 3 dB reduction (down to 12 dB now) is 16 times as long; and a 15 dB reduction means that a musician can be exposed 32 times as long as without hearing protection.

A 15-dB reduction of all music may not sound like a lot- after all, one can still hear the conductor, hear the instruments around you, and hear your own instrument- but is quite adequate to hear all of music and speech at a safe level.

Musician earplugs are flat. The Killion and Haapapuro article is a must read for anyone fitting or using musicians’ earplugs.

 

About Marshall Chasin

Marshall Chasin, AuD, is a clinical and research audiologist who has a special interest in the prevention of hearing loss for musicians, as well as the treatment of those who have hearing loss. I have other special interests such as clarinet and karate, but those may come out in the blog over time.