FAQs from MusiciansClinics.com – part 9

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Marshall Chasin
February 9, 2021

Over the next months, I will be uploading some commonly viewed FAQs from MusiciansClinics.com.  This is the website of the Musicians’ Clinics of Canada, and was completely updated over the last Christmas holidays.  I should have entitled it “What I did over the Christmas holidays”!  A full range of FAQs will eventually cover pretty much everything we know about music and the prevention of hearing loss.

Feel free to submit other questions that can be answered in 4-5 sentences and I may include them in future posts…

Can diet and lifestyle help to maintain good hearing?

Diet is obviously critical to maintaining optimal health. Drinking plenty of fluids and eating healthy (vegetarian) meals can do a lot to extend your musical career, especially if you are on the road. Many 24 hour supermarkets stock easy to prepare frozen foods that can be heated up in the nightclub’s microwave. Try to keep caffeine and alcohol to an acceptable minimum- having two beers and not four. (And of course no beer if you are under age!). A recent series of investigations indicate that hearing can be maintained if stress is reduced- stress is not just deleterious to your cardiac system; it can also increase susceptibility for hearing loss from loud music or noise.

What about smoking?

Smoking is obviously a no-no. Anybody working in a bar is getting way more smoke than their personal limit of second hand smoke, to begin with. Smoking tends to dry out your vocal chords and limits your singing range. Other than Rod Stewart, I can’t think of any other successful singer who can sing with damaged vocal chords. There is evidence that poor cardio-vascular function (commonly found in smokers) is linked to a greater propensity for hearing loss.

 

Could low-frequency hearing loss be caused by music?

  1. All music (and noise exposure) manifests itself in the higher frequency region (with the greatest hearing loss being near the top note on the piano keyboard- being between 3000 Hz and 6000 Hz). If someone has a low frequency hearing loss it is either related to the outer and middle ears (e.g. wax, ear infection, or a stiffening of the bones in the middle ear) or by an unusual condition of the inner ear. In both cases, you should seek out the medical opinion of an ear, nose, and throat doctor (an otolaryngologist). Depending on where you live, you may require a referral from your family doctor.

Can a single, short duration sound cause permanent hearing damage? If so at what level?

This is called “acoustic trauma” and is quite rare. Unlike most types of hearing loss from loud noise or music which is gradual and happens over many years, a single intense blast can create a sudden permanent hearing loss at exactly the frequency of the insulting sound. A common example is a feedback squeal from a loud speaker- a permanent hearing loss can occur and will occur at exactly the frequency of the feedback squeal (e.g. 1500 Hz). This example is not a typical frequency tested by an audiologist so care needs to be taken to assess as many frequencies as possible during testing in order to rule this out.

 

  1. Is there a reason for acoustic feedback occurring only at about 1500Hz ? I would think that the acoustics of the room , the frequency peaks of the speaker(s), and the response of the microphone and position would be contributing factors.

    1. Marshall Chasin Author

      Acoustic feedback actually tends to be slightly higher frequency than 1500 Hz but its related to the “open circuit gain” of the hearing aid system. Imagine an input somewhere in the hearing aid line, which then goes out the receiver into the ear canal, leaks back out and is picked up by the microphone and transverses to the same place as the signal was inputted. This path is related to the gain, the output, venting (intentional or not) in the earmold, the head diffraction characteristics including the presence of a hand or hat near the hearing aid, and only secondarily on the room conditions.

      Two conditions need to occur in order for there to be feedback: 1. is positive gain and 2. at or near 0 degrees phase for that frequency(ies) that have positive gain. This allows that frequency (or those frequencies) to add up constructively thereby causing feedback.

      One can “manage” the feedback by changing the positive gain (perhaps with a more occluding or better earmold) or by changing the phase, or by adding in the same offending frequency that is sufficiently out of phase such that there is phase cancellation; a technique first described in the literature in 1933.

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