Noise levels are measured in decibel, dB, with the lowest audible sound measured at 0 and the loudest sound possible reaching 194dB. The scale is logarithmic. An increase by 10 dB indicates a multiple increase in sound intensity or power.
A level of a normal conversation is about 65 dB. In most countries, a sustained noise level of 85 dB over eight hours a day in, for example, your workplace is considered the upper safe noise limit in most countries. In the US, however, the Occupational Safety and Health Administration, OSHA, still operates on the basis of a safe upper noise-induced hearing loss level significantly higher at 90dB.
Here are some common daily noise levels as listed by the San Francisco based HEAR (Hearing Education and Awareness for Rockers)-
- Weakest sound heard 0 dB
- Normal conversation at 3 to 5 ft. 60-70 dB
- Telephone dial tone 80 dB
- City traffic from inside your car 85 dB
- Subway train at 200 ft. 95 dB
- Power lawn mower 107 dB
- Power saw 110 dB
- Pain begins at 125 dB
- Pneumatic riveter at 4 ft. 125 dB
- Jet engine at take-off from 100 ft. 140 dB
- Loudest sound that can occur 194 dB
- Normal piano practice 60-70 dB
- Chamber music in small auditorium 75-85 dB
- Piano fortissimo 92-95 dB
- Violin 84-103 dB
- Cello 82-92 dB
- Clarinet 92-103 dB
- French horn 90-106
- Average walkman on 5/10 setting 94 dB
- Symphonic music peak 120-137 dB
- Amplified rock music at 4-6 ft. 120 dB
- Rock music peak 150dB
It can be a scary experience to go to the movies. But a visit to the cinema can also be unsettling for your ears. The sound levels in action films have reached staggering heights.
Improved sound technology makes it possible to turn up the volume without the distortion of the old days. But it doesn’t mean that it is less dangerous for your ears.
Researchers investigated the sound level of some recent movies. At a showing of ‘Harry Potter and the Chamber of Secrets’ they found an average sound level of 74 dB. A peak was registered at 93 dB during the battle with the snake.
‘The Lord of the Rings, The Two Towers’ was even noisier, with an average noise-induced hearing loss level of 78 dB and a peak of 95 dB. But more alarming is that the movie lasts a little over 3 hours, and that the sound level is above 80 dB for 29% of the time. This means that you are putting your ears at serious risk for around one hour while eating your popcorn and having a great time.
An average noise level of 70 to 78 dB is similar to rush hour traffic, which can be annoying but not dangerous unless you are in it for long periods of time. However the maximum levels and the percentage of time in the dangerous zone are a completely different story. A person should not, for instance, be exposed to a sound level of 110 dBA for more than one minute and 29 seconds each day.
The film industry is aware of the problem but shows no interest in reducing the sound levels, for competitive reasons. One top Hollywood producer once said: “I’m not going to make a shuttle rocket launch too low. I’m going to make it so that you feel it in your seat and in your gut”.
Nobody knows the exact number of hearing-impaired people. Professor Adrian Davis calculated about the total number of people suffering from hearing impairment of more than 25 dB which will cross the number of 700 million by 2015.
In the developed world alone, the number of hearing-impaired people will reach 215 million in 2015. Of those, some 90 million will be Europeans. In the developing countries the number is twice as large compared to the more developed world.
According to Adrian Davis, there were 440 million hearing-impaired people world-wide in 1995, and more than 70 million in Europe in a population of 700 million. According to the survey, it is found that the total number of hearing loss individual in North America to be more than 25 million in a total population of 300 million people.
The problem is growing, and Adrian Davis estimates that more than 900 million people worldwide will suffer from hearing loss of more than 25 dB in 2025. Therefore, it is best practice to check hearing impairment at the right time. Consult a audiologist as soon as possible encase of any kind of hearing difficulty.