Noise is difficult to define!
People who study acoustics define noise as complex sound waves that are aperiodic, in other words, sound waves with irregular vibrations and no definite pitch.
In engineering, noise is defined as a signal that interferes with the detection of or quality of another signal.
The combined disciplines of psychology and acoustics (psychoacoustics) study the response of humans to sound. They define noise as unwanted sound.
Is music noise? Is the hum of tires on a highway noise? Is the surround-sound movie theater noise? Is the philharmonic concert noise? And what about the accompanying beat for aerobic exercises at the health club? Sounds that are soothing for some are irritating to others.
An expert on noise, K.D. Kryter (1996) in his text , Handbook of Hearing and the Effects of Noise, (New York Academic Press) defined noise as "acoustic signals which can negatively affect the physiological or psychological well-being of an individual."
Basically, noise is unwanted sound. It is a pollutant and a hazard to human health and hearing. In fact, to me it is the most pervasive pollutant in Vietnam.
Noise in our environment affects physical heath. Noise also has psychological and social implications and affects our well being and quality of life. Let's add the damage it will cause to musician and engineer alike.
Damage to the Inner Ear Your ear receives sound waves and sends them through a delicately balanced system to the brain. Part of this remarkable system, the cochlea, is a chamber in the inner ear filled with fluid and lined with thousands of tiny hair cells. The hair cells signal the auditory nerve to send electrical impulses to the brain. The brain interprets these impulses as sound. When you are exposed to loud or prolonged noise, the hair cells are damaged and the transmission of sound is permanently altered. Noise Levels Both the amount of noise and the length of time you are exposed to the noise determine its ability to damage your hearing. Noise levels are measured in decibels (dB). The higher the decibel level, the louder the noise. Sounds louder than 80 decibels (normal conversation is at 65 decibels) are considered potentially hazardous. The noise chart below gives an idea of average decibel levels for everyday sounds around you.
Painful: 150 dB = rock music peak 140 dB = firearms, air raid siren, jet engine 130 dB = jackhammer 120 dB = jet plane take-off, amplified rock music at 4-6 ft., car stereo, band practice Extremely loud: 110 dB = rock music, model airplane 106 dB = timpani and bass drum rolls 100 dB = snowmobile, chain saw, pneumatic drill 90 dB = lawnmower, shop tools, truck traffic, subway Very loud: 80 dB = alarm clock, busy street Note: check this out, I measure the noise level in the mid afternoon in Vietnam and the meter on my SPL meter is licking the 90 dB...that is crazy! 70 dB = busy traffic, vacuum cleaner 60 dB = conversation, dishwasher Moderate: 50 dB = moderate rainfall 40 dB = quiet room Faint: 30 dB = whisper, quiet library Warning Signs of Hazardous Noise Hazardous Noise Sounds louder than 80 decibels are considered potentially dangerous. Both the amount of noise and the length of time of exposure determine the amount of damage. Hair cells of the inner ear and the hearing nerve can be damaged by an intense brief impulse, like an explosion, or by continuous and/or repeated exposure to noise. Examples of noise levels considered dangerous by experts are a lawnmower, a rock concert, firearms, firecrackers, headset listening systems, motorcycles, tractors, household appliances (garbage disposals, blenders, food processors/choppers, etc.) and noisy toys. All can deliver sound over 90 decibels and some up to 140 decibels. Can't my ears "adjust" and "get used" to regular noise? If you think you have "gotten used to" the noise you are routinely exposed to, then most likely you have already suffered damage and have acquired a permanent hearing loss. Don't be fooled by thinking your ears are "tough" or that you have the ability to "tune it out"! Noise induced hearing loss is usually gradual and painless, but, unfortunately, permanent. Once destroyed, the hearing nerve and its sensory nerve cells do not regenerate! An audiologist certified by the American Speech-Language-Hearing Association (ASHA) can conduct a hearing evaluation to determine if you do have a hearing loss. If you are routinely exposed to noise, you should have your hearing checked by an ASHA-certified audiologist on a regular basis, at least once a year. To me this is one of the most dangerous situation in 'noisy' Vietnam, especially for young infants and children. Physical Changes The most notable physical effect of noise exposure is loss of hearing . Noise Induced Hearing Loss (NIHL) affects children, adolescents, young adults, and older adults. The National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH) the National Institute on Environmental Health Sciences (NIEHS) and the National Institute for Occupational Safety and Health (NIOSH) have noted that, because of noise in our society, hearing loss is appearing much earlier in life than would have been expected just 30 years ago. Noise not only affects hearing. It affects other parts of the body and body systems . It is now known that noise: Research is on-going and continues to provide data suggesting the devastating effects of noise on health. Research is also investigating factors that may contribute to one's susceptibility to noise induced hearing loss. Other Changes Noise can also hamper performance of daily tasks, increase fatigue, and cause irritability. Noise can reduce efficiency in performing daily tasks by reducing attention to tasks. This is a concern of employers when it comes to assuring workers' safety. It is also a concern to a growing number of educators interested in human learning. Because of noise, we often find ourselves fatigued and irritable . We don't even realize the effect until the noisy hubbub stops and we feel relief. From another perspective, your own inability to hear and understand others clearly can cause you to feel angry and frustrated. Instead of accepting the problem is yours, you misdirect your feelings to others and blow up at them. Noise also makes speech communication harder. More concentration and energy is needed not only to listen and hear over the noise but also to speak louder above the noise. As a result, voices can be strained and vocal cord abuses, such as laryngitis, develop. It is a physical strain to carry on even an enjoyable conversation in the presence of noise. One demonstration of the effects of noise on behavior was done by recording how passers-by responded to a person-in-need in the presence of noise. While a noisy lawnmower was running, a woman with a broken arm dropped some books and tried to pick them up. No one stopped to help her. When the lawnmower was turned off and the scene repeated, several people stopped to help her retrieve the books. Researchers have also looked at the effect of excessive noise in school classrooms and have drawn conclusions that are seemingly obvious, yet often minimized. In one study, test results of students from a school near railroad tracks were compared to results of students far away from the tracks. Students in the quiet school performed better on the test. Another study found that students whose classrooms face noisy streets do not do as well in school as students in classrooms facing away from noisy streets. Finally, another study demonstrated that noise distracts both teachers and students. There is no question that noise is both a public health hazard and an environmental pollutant as well. Many of its effects are well known and many of its effects continue to unfold through research. Protect Yourself from Noise The key word in dealing with noise is prevention! We want to eliminate unwanted noise when we can. When noise cannot be eliminated, we want to keep it as low as possible. Here are some things to do: Hearing protectors include ear muffs and ear plugs (not swimmer's plugs), some that are custom-made and individually molded. This protection can be purchased at drug stores, sporting goods stores or can be custom-made.
- Limit periods of exposure to noise . Don't sit next to the speakers at concerts, discos, or auditoriums. If you are at a rock concert, walk out for awhile give your ears a break ! If you are a musician, wear ear protection--it is a necessity! Take personal responsibility for your hearing. Especially in rehearsal space.
- Pump down the volume! When using stereo headsets or listening to amplified music in a confined place like a car, turn down the volume. Remember: if a friend can hear the music from your headset when standing three feet away, the volume is definitely too high. Don't be afraid to ask others to turn down the volume.
- Educate yourself about the damaging effects of noise and what you can do to prevent your exposure to noise.
- Educate others and take action! Educate your children through discussion and by example. Wear your ear protection and encourage your children to follow your example. Provide them with ear protection. Remind them to turn down stereo headsets. A rule of thumb is that, if sound from a head set can be heard by others 3 feet away, it is too loud.
- Be a responsible consumer . Look for a noise rating when buying recreational equipment, children's toys, household appliances, and power tools. Choose quieter models, especially for equipment that you use often or close to your ears like a hair dryer. If there is no noise rating, contact the manufacturer and ask for one!
- Inspect your child's toys for noise danger just as you do for small parts that can cause choking. Remember, too, that children tend to hold toys close to their ear which can pose additional threat for hearing damage.
- Have your hearing tested by an audiologist certified by the American Speech-Language-Hearing Association (ASHA), especially if you are concerned about possible hearing loss. Remember the warning signs of over exposure to noise.
- Be aware of the noise in your environment and take control of it when you can. Be an advocate for reducing noise pollution.
For sound engineer and musicians:
It is hard for engineers with constant exposing to the noise level in Vietnam. I live in the out skirt of town in the USA and a very quiet town.
My engineering friends and I always wear some sort of ear protection whenever we drive on the highway. We never hardly use the iPod or MP3, our mixing level are hovering around 65-75 dB in the studio or less, we love concert and live performance but always use some audio level reducer when we are there at the venue, and if you do get stuck at a loud place, try not to get no more than 5 minute of exposing that kind of SPL to your ears. How are you going to mix if you can't hear anything? I don't care what kind of monitors you are using.
I feel sorry for the guys and gals who are working at place like the night clubs in Vietnam. I sneaked a SPL meter into Volcano night club, and the dam meter went wild at 130+ dB standing at the entrance door and as I come deeper into the club, the dam SPL meter has no where else to go.
Some of my students are DJ's at night clubs, I almost gave up on the ones that wear no ears protection while DJ'ng at clubs. They always have a hard time of getting the right tone during tracking and forget mixing altogether.
Ever wonder why some engineers could not get that guitar or drum sound, even though they did all the right steps during tracking and mixing. Most of these guys will blame the gears that they can't get...try look into your hear loss. Your problem may even be more "expensive" than you think...it is your hearing loss.
Now alcohol and smoking don't help either...seriously. With alcohol you get buzz and have less feeling to your hearing threshold, therefore loud club musics will sound bearable to you, hence the long exposure.
Musicians should always wear ear protections while practicing with the band or even by themselves. It is funny that the ears are the gateway to all 'color' of sound and I see musicians take care of their ears the least of all. I won't even mention drummers...they are brain dead.
Anyway, take care of your hearing. Learn to hear not just with your ears but your whole body, your music and sound will be long lasting, way into your old age.
Tran Duy
2 comments:
Em thay anh uong ruou va hut thuoc tinh bo. Vay sao anh noi anh huong toi tai nghe, sao anh ko ngung hut thuoc va uong ruou?
Well Cuong,
because I am the main dude around here, i can do whatever...just kidding.
Well in moderate only, I can't help the good things in life. Bad habits but I will break the cycle, so far the last time I went to the ear doctor, I am fine...so far.
regardless of the hearing loss, you can't get away from loosing some hearing acuteness as you grow older. One thing you can do is slowing everything down, hearing loss that is with age. Knowing that you can do some early prevention for your children and love ones.
btw, I stop smoking already and cut down to 1 beer a week, good enough for you?
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