Friday, November 5, 2010

The solution!

So it turns out that protecting your ears is really not that difficult after all, just requiring a little extra effort on your own.You can take measures to both protect your ears and listen to great music even at the same time.Put this into perspective, your ears are your most valuable asset, and I'm sure that the little extra effort 

Intensity: Turn it down. Simple right? Well it actually takes conscious effort to identify sources of damaging noises especially if they are not obviously ear bashingly loud. 


It’s fair enough that you have to be exposed to a certain level of noise in gigs/concerts and band practice, but just take the extra effort to ensure you’re not exposed to more than required noise in daily life. For instance, remember to turn down the volume of your mp3s. If you find that you frequently turn up the volume to mask background noise, invest in a 
good pair of isolating headphones or in-ears (The use of these earphones has been shown to provide as much as 25 dB of sound isolation and therefore most people keep the volume down), not only will your music sound much better, your ears will thank you for it.   
These run up from $20 up to a couple of thousand bucks for epic, custom fitted ones (drools)









 Remember:

Also when practicing at home try to keep the volume down on your amp, or playing softer (drummers!), saving your ears and avoiding the hassle of irate parents/neighbours/pets. Limit the time spent in risky environments like nightclubs etc where the volume is known to be extremely high. Furthermore get your band members to consciously limit their decibel output when practicing, experiment and see at what level you can play at and still have an effective practice/rehearsal. Don’t turn the volume up unnecessarily at gigs, get your sound technician to measure decibel levels to ensure the volumes aren’t going crazy. Trust me, your audience will thank you.

Environment: Another way to reduce the decibel count is by practicing in a dampened rehearsal room - one with acoustic tiles, curtains, carpet etc instead of in a small, bare, reflective room. It can make a difference of about 10 dB, that’s why pit orchestral musicians more than any other classical musician face a greater degree of risk to their hearing. 
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Alright, time to bring in serious measures for serious musicians. Hearing protection. These are a musician's best friends so listen up. I'll be arranging them from the least ideal to the most ideal forms.

Earmuffs or Earplugs: 

   

Peltor Shotgunner Earmuffs only cost $15!

Earmuffs are sold in many sporting goods and hardware shop and run from about $15 upwards. They provide good attenuation of about 20-30 dB, the downside is that they do not provide a natural listening experience, are quite uncomfortable in extended use and honestly looks a tad dorky if you're up performing on stage.

Honestly, Paul Gilbert pulls it off quite well
  Earplugs on the other hand comes in a variety of materials, foam and silicon are 2 of the more common ones (cotton wool DOES NOT work). Foam earplugs can be more comfortable, you just roll them up and pop them in your ears, the foam slowly expands and seals up the ear canal. These provide quite good noise protection, usually around 20 dB. Which is usually more than adequate. However, they tend to reduce the volumes of frequencies irregularly, often the high frequencies are muffled, which leads to very distorted sounds - music does not sound good through them. However they are cheap (couple bucks per pack at drugstores), easy to carry around and might save your ears if you’re at the front of the stage in a 100 dB concert.

Over the counter musician’s earplugs: 
ER-20

 These come in several types and designs - one of them is a one type fits all, kind of earplug with circular flanges that is designed to seal off different sizes of ears; it looks kind of similar to the isolating earphones I showed you earlier. These ones here have a fairly flat response of 20 dB (meaning that they reduce the volumes of all frequencies to more or less the same extent) for a reasonable price of $35. The ones in the picture can be found here: http://musiciansearplugs.com.au/er-20/
ProPlugs
     The second type of earplugs are Proplugs and can be found here http://www.proplugs.com/. They come in 8 sizes and covers the entire ear canal which may be more comfortable than the one described above. Since they are 'vented' they provide a somewhat more natural response than the ER-20s and at $8 a pair they are well worth it.

Finally, we have reached the mother of all hearing protection for musicians – the custom fitted hearing protection. If you are a musician and are serious about protecting your hearing, investing in a pair of these is one of the best things you can do to protect your ears. These look something like this:
 Because they are custom fitted, a visit to your audiologist will be in order (the manufacturer can direct you to a list of audiologists who carry the product). Next, the audiologist may perform a series of hearing tests for you before commencing the fitting, after which he or she would inject a plastic compound into your ears,  which will conform exactly to the shape of your ear canal and harden in a few minutes. These impressions are then sent to the company who will make the earpieces. A final visit to the audiologist would be required for fitting, along with sanding and buffing of the plugs if necessary for good sealing and comfort. 
 

These earplugs are fitted with filters which allows for a certain amount of dB reduction and can be swapped for different ones. For example, custom earplugs by Etymotic can be fitted with ER-9, ER-15 and ER-25 which provides 9,15 and  25 dB of attenuation respectively. These can be found here http://www.etymotic.com/ephp/erme.aspx 
 
These will set you back a few hundred (the ones at Etymotic cost $150-200), but for the comfort (you can wear them all day if so desired) and for the most natural sounding hearing protection available, they are well worth the cost. As a bonus they look the least dorky of the lot I’ve discussed.


Here's what Joe Satriani has to say on hearing protection:




Thursday, November 4, 2010

How much is too much??

So is this too loud then?

The key thing to understand about noise induced hearing loss is that the damage caused by acoustic overstimulation is accumulative with regards to both volume and duration of exposure. This means that a very loud noise heard for a very short time may not cause damage if the duration is sufficiently short while a loud but fairly comfortable noise level might cause permanent damage if the duration is long enough. 

This led researchers to come up with the concept of permissible daily noise dosage which takes into account the total amount of noise encountered throughout the day. Remember it's not just the music you listen to and the concerts you go to, it’s the noise of rush hour traffic, lawnmowers, the nightclubs etc that also contributes to cochlear damage.


Exposure level (dBA)
National Institute for Occupational Safety and Health Standard
Duration
85
8 hours
88
4 hours
91
2 hours
94
1 hours
95
45 min
97
30 min
100
15 min
103
7.5 min
110
1.5 min
115
28 seconds
120
9 seconds

Data from National Institute for Occupational Safety and Health (NIOSH). Criteria for a recommended standard: occupational noise exposure—revised criteria. Publication No. 98–12. Department of Health and Human Services, 1998.

Also because the decibel scale is logarithmic, notice that every 3 dB increase represents a doubling of sound intensity so don’t be fooled by the small increases in dB between loud and harmful sound levels, they actually are large increases in intensity.
 

In fact, the Australian government has recognized the need to enforce hearing protection laws in  the workplace by passing a series of legislation like the Occupational Health and Safety Regulations.

Here's a table of noise level output for common sources:

Sources of noise

Typical Noise output level (dB)
Conversation
60
Noisy restaurant/Gym/Fitness class
80-85
Circular saw/ Party/ motorcycle
88
Concert/ Live music venue
92
Major sporting event
93
Nightclub/ Rave/ Disco
97
Timpani and Bass drum rolls
106
Jet plane taking off
120
Firearm/ Jet engine
140
Rock concert/music peak
150

Data adapted from Dilon .H et al. Binge listening. Is exposure to leisure noise causing hearing loss in young Australians?

Keep in mind that the volume from personal music players/mixing studios contribute significantly to noise dosage because of the extended listening periods – one of the ways technology contributes to noise induced hearing loss (increased portability of mp3s, increased music storage, extended battery life). With the increasing trend in mp3 ownership,
be careful of the volumes mp3s are capable of putting out.
In a few CD player-headphone combinations, output exceeded 130 dB. In addition, when music is used to mask existing background noise, hearing damage is almost unavoidable.

Hopefully in light of the new information, you guys should be able to debunk the classic misconceptions about noise induced hearing loss. For example 'It doesn't hurt so its not damaging my ears' Well, the pain threshold for most people is 120 dB which is certainly high enough to permanently damage hearing. Also 'It's only for a little while' Look at the table, sounds levels at 100 dB, the sound level at lots of gigs can damage hearing in 15 minutes, but when was the last time you went for a gig that lasted 15 minutes? In fact, remember Pete Townshend? The loudest concert ever recorded as listed by the Guinness Book of Records was the concert by The Who at the Charlton Athletic Football Club, London, on 31 May 1976 with a volume level of 126 dB 32 meters from the stage! 



In summary, here's a series of questions that may be helpful to you in identifying if you are at risk of hearing damage and should be used as warning signs:

  1)  Do you notice ringing in your ears after noise exposure? Ringing in the ears (tinnitus) is a common byproduct of excessive noise exposure, it usually goes away after some hours or a day but too much of these incidents could lead to permanent tinnitus and noise induced hearing loss. If the tinnitus persists for an abnormally long time (eg more than 24 hours), seek prompt medical advice from a professional like an audiologist to get your ears examined.
  
 2)Do your ears hurt upon exposure to the music or sound? If the sound causes pain it is hazardous. The acoustic pain threshold is usually 120 dB so it is safe to say if the sound hurts your ears immediately seek a quieter environment, don’t be fooled that it doesn’t hurt after awhile even when the same sound is playing, it might mean that temporary hearing loss has occurred and the damage is ongoing, even if the pain has gone.

3)  Do voices sound muffled after you have been around music for an extended period of time?

  4) Does music sound distorted at the end of the day?

  5) Do you have difficulty listening to the radio in noisy settings or following conversations in a group?

If the answer is Yes to any of the above questions, it would be wise to seek protective measures and a visit to your audiologist might even be in order for a complete auditory evaluation
     
A Also as a rule of thumb, the noise level is about 80 dB if people have to raise their voices to be heard at a distance of 1 meter
   
  If people have to should to be heard at a distance of 1 meter, the noise level is about 90 dB,
  
  And if you have to shout in your friend’s ear to be heard over the noise, the noise level is …way too loud!

Problems, problems, problems. Well its not quite enough to be aware of the problems, we have to be able to solve them in order to enjoy the things music we love, safely. That's where the next section comes in


 
...The Solution!



Wednesday, November 3, 2010

Mechanisms and symptoms of noise induced hearing loss (the sciency bits)

  So today I decided to get stuck right into the technicalities of noise induced hearing loss, namely, what are the mechanisms of hearing loss and how they relate to their symptoms. Don't get me wrong, while I managed to find some really interesting information, it took some serious academic trawling through long paragraphs and even longer journals in the quagmire known as PubMed..egh.
I mean, can't they just word their titles like normal ppl?
Ok. *deep breaths* 
Enough ranting.

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       The initial effect of high intensity sounds is an involuntary muscle contraction in the middle ear called the acoustic reflex produced by the body to protect itself. This reflex begins to be activated by sound intensities greater than 80-85 dB. This reflex consists of the contraction of small muscles attached to the malleus and the stapes which have the effect of reducing middle ear bone movement and hence reducing the amount of vibration passed along to the cochlear, sparing the delicate hair cells. 

 This causes what is known as ‘temporary threshold shift’, which explains the stuffiness and ringing sensation (tinnitus) goes away after a day or so. Tinnitus is a common byproduct of having been 'acoustically overstimulated' and should be taken seriously as a sign to ‘rest’ your ears.

 A temporary threshold shift of 25 dB means that a sound has to be 25 dB louder to be perceived at the same volume than before the threshold shift occurs. The degree and recovery from a temporary threshold shift is affected by the intensity of the stimulus, the duration of the stimulus and individual susceptibility. If such overstimulation is repeated, usually over years, then the threshold shift will become irreversible, that is a permanent threshold shift, or noise induced hearing loss. This is caused by the death of overstressed cochlear hair cells and is termed 'sensorineural hearing loss' because this type of hearing loss involves a loss of sensory capability (in contrast to conductive hearing loss which is an impairment in the transmission of sound energy to the perfectly functional cochlear hair cells), so sound energy is getting into the cochlear just fine, but the deficient hair cells are unable to pick up all of the signal.

Noise induced hearing loss initially occurs at 3000-4000 Hz, this is the upper range of conversation and the person might have problems differentiating consonants like ‘s’ and ‘t’. With continued overexposure, hearing loss will spread to both higher and lower frequencies.

Here's a video I found that really helped my understanding of how noise induced hearing loss is really like.
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Simulated Sensorineural Hearing Loss:



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The difficulty in identifying noise induced hearing loss is the fact that the symptoms occur slowly and gradually over many years and significant hearing loss only becomes evident until significant, permanent damage has been done. 

Also the gradual loss of hearing and the increasing dependence on visual cues like lip reading often goes unnoticed so these sufferers have no idea that they’re having hearing problems since normal conversation is unimpaired.

Permanent damage to the cochlear hair cells is caused by acoustic overstimulation for a too long a period (a fancy way of saying, too loud for too long). This is caused, partly by the overproduction of reactive oxygen species and free radicals in the hair cells from acoustic overstimulation (Interested readers can consult this link http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/ROS.html). These reactive oxygen species and free radicals break down cellular components and damage DNA, ultimately resulting in death of the cell. Cochlear hair cells do not regenerate so once killed, frequency sensitivity in the range where the cells were responsible for is lost.              



    
As you can see from the above pictures, there is significant abnormality in cochlear architecture associated with the damaged hair cells.
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 ‘I hear all right, but everyone’s mumbling’ is a common complaint for unwitting sufferers who have trouble differentiating sounds especially in crowded locations. For musicians, such impairment in pitch discrimination can be quite deleterious to for example, the perfection of a performance.
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For a taste (or a hear? Sorry, bad pun) of how such hearing impairments affects music perception:
Stimulated hearing loss - Music



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Congratulations, you've come to the end of a very long and wordy post.

Until next time...
The crucial question: How much is too much? 
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Noise induced hearing loss...its more common than you think..

  Noise induced hearing loss has plagued musicians for over centuries. Musicians being exposed to music (often at loud volumes) for extended periods, there is an ever present risk of developing noise induced hearing loss and tinnitus. Simply put and just for the sake of perpetuating cliches - it comes with the territory.

  Today I decided to actually research on some real life experiences of musicians who developed noise induced hearing loss.       
  Hopefully, its going to be a blast.

  Not being a classical musician myself, it was surprising to find that classical musicians too are vulnerable to noise induced hearing loss since I always associated classical music to peaceful, soothing Mozart. However, a study at Sweden’s Concert Hall and Lyric Theatre in Gothenberg revealed that 59 out of 139 orchestra musicians (42%) had hearing losses greater than that expected for their ages. Pit orchestra musicians may be at particular risk because their music is played in a confined space. 



Particularly damaging are brass instruments (originally designed to produce enough volume to hurl across the battlefield), now blasting 120 decibels at the point of delivery - about the same volume as a jet taking off - at the poor viola player who sits in front.  
Then
Now
       
 
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The Contractions



    Obviously rock music, played loud and fast and soundin’ so good, also have the capacity to damage hearing. In fact, many notable rock musicians have reported noised induced hearing loss. Among such musicians is one by the name of Kathy Peck, who played bass for the all-female, punk band The Contractions in the late 70s producing high volume, fast and fun music - too loud it turned out, because after a gig opening for Duran Duran, she permanently damaged her ears, losing her hearing and also experiencing tinnitus.

She then went on the co-found H.E.A.R, Hearing Education and Awareness for Rockers.
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Hearing Education and Awareness for Rockers:



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Pete Townshend: Rock induced hearing loss
                   Another notable musician who suffers from noise induced hearing loss is Pete 
Townshend who rose to fame being the guitarist and songwriter of the English band The Who, one of the most influential bands of the 60s and 70s. He has severe hearing loss in his right ear which he attributes to the sound of his guitar and the drums and also from an explosion when Keith Moon, drummer for The Who, blew up his drum set live on stage.
The Who

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Pete Townshend on his hearing loss:



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“I have severe hearing damage. It’s manifested itself as tinnitus, ringing in the ears at frequencies I play guitar…It hurts, it’s painful, and it’s frustrating.”
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   Another notable musician with hearing loss is Mick Fleetwood, the drummer for Fleetwood Mac, a successful British-American rock band in the mid-70s: 
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“The world's worst is when you find yourself going like Mother Hubbard and cupping your hand behind your ear. I was a major glutton for volume: Gotta feel it, gotta hear it. Sooner or later you're going to pay the reaper."
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Moral of the story so far: Noise induced hearing loss affects the best of us. PROTECT YOUR EARS!


Now, onward to the next part of the story: How noise induced hearing loss actually works.

*Warning, Science ahead*


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p.s: 
Oh yeah, for those wondering how one explodes a drum set, here's the video:

Keith Moon´s drum kit explodes:





Monday, November 1, 2010

The trail begins here..

To appreciate hearing loss, obviously the trail has to begin right at the basics - What is sound and how is it produced:
*WARNING, Science ahead*
 Sound is produced by a mechanical force such as a vibrating string which exerts force on air molecules . This repeated compression produces periodic wave-like air pressure variations which enter the outer ear and strike the eardrum, setting it vibrating. 


The sound waves are then transmitted through the ossicles (3 small bones in the middle ear), through to the inner ear and the cochlear, a coiled snail-like organ containing fluid. The cochlear contains the organ of corti, which contains highly specialised hair cells which is stimulated by the vibrations in the cochlear, sending electric impulses to the brain which we interpret as sounds. 

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Here's a nice video that i found:



I'll leave it here for now (gotta run,dinner work awaits), but next time we'll get right into the interesting stuff- *crosses fingers* as I do more research on this topic.


p.s:  man, this feels like such a school assignment now :(

Schoolwork? Bleh.