Say What? Noise Levels in a Civilized World

September 2006

Say What?
Noise Levels in a Civilized World
by Dan Richards

It's all around us. We swim in a sea of noise. In this new millennium society we're bathed in iPods, construction sites, roaring traffic, power tools and a myriad of other sources of deafening sound that assault our systems on physical and psychological levels. Along with Don Campbell, author of The Mozart Effect, "I am not a member of the sonic police". On the other hand, a little awareness can go a long way in the prevention of hearing loss.

I've been asked the question, "Would you rather give up sight or hearing if you had to lose one?" Morbid question. Most of us usually would choose to lose our hearing rather than sight. Hearing appears to be the lesser of the two senses. Most of us carry sunglasses for eye protection when we know we'll be in conditions that may harm our eyes or cause discomfort. For ear protection, most of us don't even have a set of ear plugs. This isn't an article to tell anyone what to do. We all have a right to cook our brains and ears with loud noise. Along with that, we also have a right to protect ourselves with information to further the awareness of the sound levels that surround us and how it affects us over time.

Have you ever been standing six feet away from someone listening to an iPod, and you could hear the music? Inside those mini headphones, that music fan is literally frying their sensitive ear drums. Of course it doesn't happen all in one day. Loss of hearing occurs gradually, often it's too late by the time significant damage is noticed. We usually cover our ears for very loud noises, but even loud volumes that aren't painful can chip away at our hearing. How much is too much noise? Sound is measured in decibels (dB). On the right is a chart of sounds commonly occurring in the environment.

Exposure of periods exceeding eight hours of sound levels over 90 decibels can, over time, result in permanent hearing loss. Most of the concerts that we've all attended are performed by artists wearing ear plugs. If the audiences truly idolize and appreciate the performers, they'd take the tip as well and pop in some plugs. The music, believe it or not, can still be heard and enjoyed without the side effects of ringing ears and even headaches afterwards. Some bands even sell ear plugs at the shows.

How Do These Things Work?
So how do these ears of ours work? What are they made of, and how do we hear?

Our ears are delicate instruments with numerous parts that are designed to interpret the information received and send it along to the brain for processing. Impulses are transmitted to the brain by small hair cells in the inner ear which stimulate the auditory nerves. The middle ear is where the eardrum is located and it is there that the incoming sound waves cause vibrations. These vibrations travel through a fluid within the cochlea of the inner ear and are picked up by the tiny ear hair cells and nerve endings. This process can be damaged through repeated exposure to high noise levels. Excessive noise can damage the delicate hair cells, at which point the auditory nerve is not sufficiently stimulated. It tends to start with a loss in the higher frequencies, which ironically, makes us want to crank it up even more for the desired results. This action is something like a drug, in that it takes more to "get off". After a certain length of time, it just becomes a vicious cycle. Eventually, even the equilibrium can become affected because head position and balance are all part of the same system. We've all felt out of sorts when we have colds and are "plugged up".

Rock On!
Here's a simple online hearing test. Take it with a grain of salt, but hopefully it can add a small amount to general awareness. Along with that, here is more information on noise levels.

Studies have shown that a sixty-year-old from a traditional African society hears as well or better than a twenty five-year-old from North America. This has frightening implications. Children are subjected to noise levels at video arcades, monster truck shows and concerts that can exceed 120dB. All this in good fun and family entertainment. At some point these sound levels are just plain criminal, and as we move into this next century we might even begin to see more laws and legislation on tolerable noise levels. But what's important is our own awareness that there are sources of noise in our environment that are literally robbing us. In this case, not blind, but deaf.

END

Dan is the editor of Studio Reviews Magazine. He is a multi-instrumentalist, songwriter, engineer and producer. He was a 115th AES Panelist in NYC for the tutorial seminar, "All About Microphone Preamplifiers". He is interviewed in the Nov/Dec 2004 issue #44 of Tape Op magazine.
Dot is currently producing and engineering The Listening Sessions where he has spent the last few years using and listening to over 100 preamps/DI's and over 200 mics, and recently completed recordings with Terry Bozzio and Ronan Chris Murphy. He co-moderates the Recording Forum with Ronan Chris Murphy at Studio Forums.