Noise pollution is all around us, especially in the major cities of the world. Experiencing this cacophony of sound is often disorienting and fatiguing. From the moment we step out our front door we are bombarded with a cluster of city sounds. Unlike our eyelids, we cannot close our ear canals. But many of us use headphones and earbuds to block out the world, sometimes at unsafe volumes. Knowing how loud is too loud is important to know...
The use of portable music players/iPods allows us to drown out the sounds of the city. These earbuds and headphones serve two purposes. First, they provide music reproduction for listening pleasure. Second, they passively (and sometimes actively) reduce sound from the surrounding environment. While reducing unwanted noises is a welcome, directly injecting sound into your ear can pose some risks.
Although hi-fi speakers can be turned up to ear damaging levels, they have the advantage of not being strapped directly to your ear canal. Even more, speakers produce sound that travels through the air before it reaches your ears. Since air is an excellent absorber of sound, the overall sound pressure level will be reduced before it hits your ear drum.
Private listening sessions on headphones and earbuds can be enjoyable, but you must excersice caution not to listen too loudly. A great article on "preventing hearing damage with headphones" can be found over at Headwize with tips for safe volume settings:
OSHA Regulation 1910.95 - Occupational noise exposure; decibel levels of musical noise.
Indoors in a quiet listening environment: According to the Airo study, listeners in a quiet room set headphone volumes at an average of 69 dB, a little less than the average sound level in a restaurant. With open-air headphones, the ability to hear normal conversation through the headphones is a good indicator that the volume level is safe. Because closed-ear headphones acoustically isolate the listener, normal conversation may not be audible when wearing these types of headphones. Instead, a safe volume level may be set by moving one earcup off and comparing the level in other earcup with that of normal conversation.
Outdoors on a busy street: The average sound level on a busy street is about 80 dB. In the Airo study, when the outdoor noise was a mere 65 dB, listeners raised headphone volume levels to over 80 dB. Therefore, on a busy street, levels would likely have to be dangerously high to drown out ambient noise - especially if open-air headphones are used. While the Airo study recommends not using headphones in such noisy conditions, if the listener insists on musical accompaniment outdoors, closed-ear headphones and canalphones that substantially attenuate ambient noise may allow for safer listening volumes.
Our hearing is an integral tool used for communication, balance, and localization. The human auditory system is truly remarkable and sensitive. An audiologist can advise you on hearing protection options to help maintain the longevity of your hearing.
Another option is to use AUDIO-CD Hearing Test, a self-administered hearing test designed for home use. The test is performed over a range of 24 frequencies -- from 20 Hz, the lowest frequency humans can hear, to 20,000 Hz, the highest frequency humans can hear. All you need to perform the test is a CD player and a set of headphones or earphones. Better safe than sorry!
This post was originally written by Vahan Baladouni of HIFIQC (High-Fidelity Quality Control) and reposted/edited with permission.
(Images: Vahan Baladouni, Gregory Han. Chart via )