Are you Wired for Sound?
Do you know How to Check your Earphones or Headphones for Safe Sound Levels?
Are you already worried that your hearing is deteriorating, unable to hear the alarm clock in the morning, tuning out high frequencies! Do you just want to know what you can do about damage prevention ? If yes, then read on.
Dangers of hearing damage with headphone usage
Headphones or earphones may look relatively harmless compared with Giant PA stacks or studio monitors.
However, the important factor is not size in this case, it is how much sound it takes to cause your eardrums to vibrate.
So bigger is not always more, and headphones can cause more damage to hearing as they can in fact give noise exposure well above the accepted safety limits. So it is good to know that;
- Your brain isn’t fooled into thinking the sound is “out there” so;
- It expects it to be loud, your brain that is and not the neighbour’s cat
- Privately, just between you and Bon Jovi or Meatloaf:
- Meatloaf will not complain if it is too loud unless he happens to be your next door neighbour
- Whether it is domestic equipment for professional use or professional equipment for domestic use it can still be harmful!
Unpleasant Sounds v Harmonious Music v Speech Sounds
Surprisingly the harmful effects are about the same for both industrial noise and music.
Many people are surprised to learn that loud music can be harmful and damage our ears.
Even more surprising is speech sounds (used more in the workplace for telephone operators) can be harmful due to the sheer length of time spent at work. For such people good noise excluding earphones are vital.
Health & Safety (ISO 11904-2) specifies how to measure sound;
“Acoustics – Determination of sound immission from sources placed closed to the ear – Part 2. Technique using a manikin “
It is good to know that no human or animal is going to be harmed in testing the measurement of sound directly into the ear!
This international safety standard is the standard technique used for measuring sound from headphones.
It is not possible to get an accurate measurement of sound with headphones with a standard sound level monitor.
To get real precision a “dummy head” also known as an acoustic manikin can “wear” the headphones for the purpose of measurement. A comparison of sounds is necessary; so imagine the usual background of noise in a factory and the noise from headphones. One of the problems with headphones is that as they are close to the ear, the outer ear and inner canal act as amplifiers of sound naturally thus making us more sensitive due to the proximity.
So in other words the actual amplification of headphones or earphones has to be adjusted for comparison purposes, maybe by 10 dBs.
Who is most at risk?
People working in noisy environments including;
- Factory workers
- Sports commentators
- Camera operators
- Call Centre operators
How can I protect myself?
- By restricting the power of the equipment being used
- Fitting the earphones with a limiter in the lead or built in to the earpieces
- Using specialised limiting equipment (check out specialist equipment manufacturers)
Restricting the power of the equipment is fine if you are only using one or two types of equipment as in suggestion number 1.
Most modern earphones are very sensitive working well with battery operated gadgets like mp3’s, hence when you plug them into mains electricity they will produce a powerful sound.
Unless you are sure of the safety level it is worth getting measured, especially if you are unsure of the power of your equipment and the decibel system.
Although method 2 is simpler it can throw up some disadvantages when you need clarity of sound or have to listen critically. The dynamics may not be loud enough if the limiter is set at a guaranteed safe level.
Method 3 is going to ensure that DJs and others working with headphones are listening within legal exposure limits.
Why Sound Level Limiters?
Sound level limiters are fairly new to people who are not working in broadcasting.
Whilst they are now available in the domestic market they may not meet the rigid standards of those used in industry.
They can be adjusted to suit different types of earphone or can be integral, they are fitted inside a small plastic box and do not add to the electrical load having no battery or external power.
All these tips refer to “earphones” as a generic term for transducers that make sounds close to the ear or in the ear and refer to headphones, headsets and even hearing aids.
Love them or hate them, it is good to know that there are international safety standards in place to protect our hearing.