Tuesday, 18 June 2013

Look after your hearing!

Once upon a time I used to drill, angle grind, circular saw - you name it - with scarcely an item of safety gear on.  After two incidents where I put small fragments of metal in my eye I learnt to wear safety glasses, but it wasn't until much later on I finally heeded the advice: "JAW, wear hearing protection."

Suffice to say, for quite a number of years now, I won't even pick up a hammer without having safety glasses and hearing muffs on.  But, damage to my hearing had already started.  Irreversible damage.  Yes, I have minor noise-induced hearing loss and minor tinnitus (a "ringing in the ear when no sound is present").

Hey don't feel bad for me, it's very minor comparatively, I only hear the tinnitus when the background noise is very low.  The hearing loss only affects me when there is a lot of sound coming from all around and I'm trying to listen to something specific.  Just take note: if you are doing something - power tools, listening to loud music, that sort of thing, and you come away with a ringing in your ears then that was too loud.  Keep a few pairs of ear muffs around the house and a few rolly squeezy type inserts on hand and turn it down.  That ringing in your ear, which goes away after a day or so?  My tinnitus is very similar to that sound, except it doesn't ever go away...

The noise induced hearing loss, well, let me try to describe it.  You might actually have it and don't realise.  Now would be a good time to stop it getting any worse if you do.  What, you are fine, you can hear a pin drop?  So can I.  In the quietest of quiet rooms I could hear a flea on a mouse squeak.  That's not how hearing loss happens.  However, if you put me in a room where several people are talking, and someone is talking to me - right there, right in front of me - I can't understand a word they are saying.  Why is that?

As it was explained to me, which makes a lot of sense, it's the high frequencies that are lost first.  High frequencies are where the data is.  Think about wireless data, or radio transmissions: the higher the frequency, the more data you can fit in it.  And even though the main component frequencies of the human voice are generally lower than 1kHz, the "sss"ses, are up as high as 8kHz.  That holds more information that you'd think.  Let me see if I can simulate noise induced hearing loss for you.

First, here is me saying something Ocker.  Yes, I am a bit "nasal", that's why I don't sing:

Now here is the same thing with everything above 1kHz removed.  It sounds "mumbly", but you can still tell what I am saying:

Here is me saying the same original thing again this time over top of a crowd of JAWs all saying Ocker things.  At about the 3 second mark you can hear me pretty clearly over top of those other noisy JAWs:

Same thing, except the talking over the top has everything above 1kHz removed again.  You can still hear me, but it is more difficult:

And that's where the problem is.  In a noisy environment, you can't "hear" (where "hear" means "understand") the important stuff - that high frequency data is lost.  People with this sort of hearing loss, as it progresses, may start to withdraw from crowds, perhaps leading to other psychological problems.
But like I said I'm not too bad.  I do struggle in a noisy environment, and yes, I don't go into a loud music environment.  I do ask people to repeat themselves quite often, and will get up close to hear them.  I notice people get a bit annoyed if you ask them to repeat themselves for the third time...and if I still didn't understand them I smile, nod my head and play along like I did hear them.  Ah the social techniques of hearing loss...

Bottom line - protect your hearing!

1 comment:

  1. Sadly, my roomy/inlaw/buddy/person who 1st allowed me to touch his old Takamini, the 1st guitar I put my hands on. He has the same thing but worse. Years in a wood/metal shop/forge have taken their toll and he is just now getting over the "I'm too manly for protection" stage. Now it is an exercise in preventing more damage than preventing it in the 1st place. This is a very real concern for musicians.