IEMs, or In-Ear Monitors, which were hitherto the reserve of audiophiles with deep pockets, have now breached the mainstream. These earphones have even replaced the ubiquitous stock earbuds bundled with smartphones and PMPs (Portable Media Players). There's a genuine reason for this shift from earphones that rest on the ear to those designed to enter the auditory canal.
Originally conceived for musicians and audio engineers, IEMs started life as custom-moulded earpieces created with the sole purpose of achieving optimum mechanical noise isolation in busy live and studio environments. What was envisioned as professional equipment enabling musicians to monitor their feed during live concerts, eventually gained popularity due to its unprecedented feasibility as a portable audio solution. It wasn't long before audiophiles caught on the IEM's ability to reproduce fine details and, more importantly, attenuate ambient noise to a great degree.
A surprisingly small percentage of users genuinely know how to use them effectively, since this type of earphones is relatively new. The very nature of their fit and working principle makes them sound spectacular when worn right, but any mistake in that respect translates into a severe compromise in the overall audio quality. Worse yet, in most cases the penalty goes beyond that, because improper usage can potentially cause permanent hearing loss as well. This guide, therefore, focuses on what constitutes hearing loss, how improper IEM usage is a contributing factor, what should be done to prevent that, and finally, how to get the best out of your IEM.
Understanding Hearing Loss
The concept of permanent hearing damage for most people involves sounds present at or above the threshold of pain, which occurs at 130dB. Such damage is generally reversed in 16 to 48 hours, but hearing loss can be irreversible if the cochlear cells (inner ear) are damaged. This sort of ear trauma is caused by exposure to transient sounds such as explosions or passing jet planes in proximity to the listener.
Protecting what matters the most (image source)
However, any sound over 85dB can potentially cause hearing damage. The only difference being that it takes around eight hours of continuous exposure at that noise level before hearing loss sets in. For every 3dB increment thereafter, the permissible exposure time is cut down in half. That means, you'll damage your hearing in just four hours at 88dB and two hours in 91dB, whereas sounds at 115dB just take approximately 30 seconds to have the same effect.
While louder transient sounds instinctively prompt us to safeguard our hearing, it is those of a lower magnitude that tend to be more insidious. Loud music is the best example since that's more likely to be heard long enough to cause irreversible auditory damage. In fact, permanent hearing loss attributed to long spells of chronically loud music through earphones is more common than you'd imagine.
I have personally witnessed quite a few cases where people have suffered anywhere between 10-15 percent hearing loss due to long-term exposure to loud music. This is a genuine problem that should be addressed by creating awareness and good practices for enjoying music on the go.
IEMs and Auditory Damage
Let's just get this most common myth out of the way: IEMs are more dangerous due to their proximity to the eardrum. This couldn't be further from the truth. When used in the right manner, they are just as innocuous as your regular earbuds or headphones. In fact, the way they function makes them less likely to cause ear damage. It's all down to the physics.
The power requirement of a transducer (speaker) is directly proportional to the volume of air it has to move. Because IEMs create an airtight seal and have to deal with a considerably smaller acoustic chamber, they must push only a miniscule volume of air. They, therefore, have to radiate a surprisingly less amount of energy to generate the same SPL (Sound Pressure Level) as larger headphones. This actually puts less strain on your eardrum.
However, an IEM loses its efficiency significantly when this airtight seal is broken. When that occurs, the drivers have to work extra hard to overcome the ambient noise that's free to leak in as a consequence. The extent of harm caused by this combination of high volume and loud ambient noise is best illustrated by conducting this simple experiment:
- In a quiet room, play one of David Attenborough's documentaries on your TV set.
- Reduce the volume levels down until you can just about comprehend Attenborough's commentary.
- Note down the volume level and maintain it for five minutes.
- Now, play some loud music (preferably Death Metal) on the music system at as high a volume level as you can endure for five minutes.
- Turn off the music system and try listening to the voiceover on the documentary.
Unless you happen to be the Son of Krypton, you should not be able to comprehend Attenborough's commentary anymore. That's because your brain has attenuated your hearing capability in order to reduce discomfort. To put it simply, as ambient noise increases, you need higher SPL to create the same amount of perceived sound. Your eardrum nevertheless is bombarded with a much higher sound level, which doesn't bode well for your ears at all.
Getting a Right Seal
The above example should explain why IEMs are best suited for outdoor usage thanks to the excellent mechanical dampening afforded by their airtight seal. This is largely dependent on choosing the right sized ear tip though. More often than not, the average user ends with one that cannot ensure a good seal. This is mainly because the typical Indian ear (auditory canal) is smaller than its American or European counterpart. Using the default medium-sized tip, therefore, is a bad idea for the average Indian.
Trying out different tips is the very first thing you should do, because a right sized tip allows deeper penetration into the ear canal. This is of utmost importance, because using an oversized tip that doesn't fully enter the canal makes music sound tinny and thin. Perfect fitting IEMs not only provide a noise-isolating seal, but they also improve bass and the overall music tonality.
Maintaining a Safe Volume Limit
Although IEMs provide noise attenuation, they aren't perfect. With high enough ambient noise, there's a risk of cranking up the volume levels beyond the threshold of safe hearing. The best way to prevent that is by determining this threshold and making a point not to exceed that volume level. This is the best way to go about doing that:
- If your smartphone or PMP has an auto-volume levelling feature, it's wise to let it equalise the levels between different recordings.
- Go to a quiet place and listen to music at a volume level that you can comfortably sustain for extended listening sessions.
- Make a note of that volume level and do not exceed it under any circumstances.
If you ever have to exceed this volume level, that means either your earphones cannot provide enough sound isolation, or the outside noise is unacceptably high. In both the cases, the best course of action is to stop listening to music altogether.
Wearing IEMs the Right Way
The lack of proper seal is the most common reason why IEM users listen to music at chronically high volume levels. You may choose the right tip, but that amounts to nothing if you don't know how to wear them the right way. It's staggering to know how few IEM users actually manage to get that right. If you think you aren't one of them, fret not, because here's how it's done:
Lifting the ear straightens out the auditory canal
Open the mouth slightly to enlarge the ear canal
Gently twist the IEM while inserting it
- If your IEM is outfitted with foam tips, they should be rolled thin between your palms before insertion.
- Hold the right-hand-side IEM with your right hand.
- Reach over your head with the other hand and grasp the top of your right ear.
- Pull the ear up and slightly outwards and hold it there. This straightens the natural curves in your ear canal.
- Open your mouth slightly to expand your ear canal.
- Gently screw the IEM inside the canal till you have achieved a perfect seal.
- Repeat the same for the other channel.
Never remove the IEMs in a quick motion. Always gently twist them in/out to prevent vacuum build up (while removing) and air pressure (while inserting) from damaging your eardrums. Although the phenomenon isn't harmful, IEMs cause a marked increase in the production of bacteria in your ears. For this purpose, do let your ears breathe after extended periods of usage. Doing so also prevents fatigue and allows your ears to recover.
Remember that your body treats IEMs as foreign bodies, which leads to an increased wax production. It's therefore a good practice to clean your IEMs as well as your ear canals on a regular basis. Following these tips will not only safeguard your hearing, but will also deliver a palpable increase in bass response and attenuation of external noise. This is definitely worth the extra effort and the slight embarrassment the elaborate ritual may cause in public.
Published Date: Jan 23, 2013 19:19 PM | Updated Date: Jan 23, 2013 19:19 PM