WILLY T talks HEARING LOSS from prolonged exposure to loud noise.

 
I know that we all say “if it’s too loud, your too old” but if we want a long term career in live sound we have to start looking after our ears! We have all occasionally experienced hearing that seemed dull or muffled, or had a ringing or buzzing in our ears after a mega rock gig or a big night of clubbing. These are all signs that damage has occurred to our inner ear. If our hearing were to be measured straight after the gig, it would be temporarily reduced. This is called Temporary Threshold Shift (TTS). TTS and ringing are signs that the noise or music level is too loud.

With rest – away from all sources of intense or loud noise – your ears probably recuperated and were functioning normally within 48 hours. Within 16-18 hours, hearing should return to the pre-exposed level while the ringing in your ears – tinnitus – may continue for several days.

However, with repeated exposure temporary hearing loss becomes permanent loss.

It is believed that a temporary hearing loss occurs when hair cells in the inner ear have been bent by vibrations and need time to bounce back to their original position, or when the fluid in the inner ear has changed chemically because of over-stimulations, and needs time to revert to its original composition.

Permanent hearing loss – also referred to as Permanent Threshold Shift (PTS) – is the result of the delicate hair cells snapping or total nerve destruction within the cochlea. Once these important parts of the hearing process are destroyed, they can never be restored or regenerated. With current knowledge and technology, we cannot fix an inner ear hearing loss – aka sensorineural hearing loss. The techniques used to fix some of the thousands of nerve endings in the inner ear would be the same techniques required to enable a para-wheelie to walk.

THE SCARY PART

Permanent noise-induced hearing loss can occur as a result of prolonged exposure to noise or music if the loudness is greater than 85 decibels (dBA). The longer we are exposed to a damaging level the greater will be the eventual hearing loss.

There is a relationship called the ‘Exchange Rate’ between how long you are exposed to noise and the damage done at a certain level. This where things become very scary! The louder the sound, the less amount of time we have before ear damage starts to occur. For every 3dBA increase in noise exposure, the damage doubles. Or put another way … every 3dBA increase in noise means we can stay for half the time before ear damage starts to occur.

For example, exposure to 85 dBA for 40 hours a week = 88 dBA for only 20 hours, 91 dBA for 10 hours, 94 dBA for 5 hours, 97 dBA for 2.5 hours, 100 dBA for just over one hour each week. 110dB – Rock  band – Regularly more than 1 min = permanent hearing loss! 120dB – Nightclub –Threshold of sensation – Regular exposure of more than about 10 seconds risks permanent hearing loss!

GOT THE MUMBLES                                                                           

Hearing loss occurs so gradually you probably won’t notice it at first. Noise – or music-induced hearing loss tends to affect the higher pitches first, including sounds such as those of violins, a watch ticking, and some constant sounds (s, sh, f, and th). Hard of hearing people generally retain excellent hearing for the low pitch sounds, such as those made by cars on the street, people knocking on the door, and vowel sounds (a, e, i o, u). As a result, people with music or noise-induced hearing loss – or everyone’s Nanna – often say: “I can hear you okay, but you’re mumbling.” Approximately 60% of speech intelligibility comes from the high pitched sounds or consonants. Understandably, if high-pitched sounds cannot be heard, speech is no longer clear. Hearing loss of this type results in a loss of clarity and not necessarily a loss of loudness.

People with noise-induced hearing losses typically have reduced hearing for high pitch sounds (that is, for frequencies between 3000 and 6000Hz). In general, the louder the noise and the longer you are exposed to it, the greater the amount of hearing loss you will suffer.

A QUICK HEARING TEST

You can do a quick hearing test before and after you go to a noisy gig or full-on club. Before going in, tune your car radio to an all-talk news station and adjust the volume so that you can just barely understand the conversation. After returning to your car after the gig – without adjusting the volume control – see if you can understand the conversation. If you cannot, then you probably have been overexposed to the noise or music.

FINALLY

The issue of hearing damage at gigs or at nightclubs is one that is not given the importance it deserves. Combine ambient noise with the ubiquitous iPod and we are facing a generation of punters with permanent hearing damage. Pros within the industry are well aware of the damage that excessive noise levels does to their ‘money maker’ ears are.

On the legal front it is only the fact that hearing loss cannot be blamed on one venue or gig that no one has been sued for damages. One day ambulance-chasing-lawyers will find a way to blame an individual venue or act, and sue them. When that happens, lawyers will make LOUD gigs disappear like they did to the tall slippery slides in children’s playgrounds! You have been warned!

So if ya wanna hear all the gig, do what the pros do and look after your ears. Like teeth you don’t get a second set! [Not the best analogy, but you get the idea – Geared Ed.]

WILLY T runs Giraffe Media. Providing Words, Pics and Live-Audio Recording Services to the entertainment industry. Email for more information.

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