How loud is your iPod?
What is the definition of Loudness?
When you notice a difference between loud sounds and quiet ones, your ears are perceiving changes in sound pressure level. Intensity (or volume) is measured in decibels (dB). Zero (0) dB is the softest sound that can be heard. Normal conversation is around 40dB to 60dB, a whisper around 30dB. A rock concert can average between 110 and 120 dB. Pain from hearing is subjective. Levels below 125 dB may be painful to some individuals. The sound from a jet plane is approximately 140 dB.
Is loudness linear?
No. Decibels are measured on a logarithmic scale. Each increase of 10 on the scale represents a tenfold increase in loudness. 20 dB is 10 times as loud as 10 dB; 30 dB is 100 times louder than 10 dB, and so on. If you owned a 100W home audio system, and you wanted to buy one that was twice as loud, you would need to buy a 400W system!
So is it just loud noises that make you deaf?
Yes, but duration of noise is also very important. The maximum exposure time for unprotected ears per day is 8 hours at 90 dB according to The Occupational Safety and Health Administration (OSHA) guidelines. For every 5 dB increase in volume, the maximum exposure time is cut in half.
- 95 dB - 4 hours
- 100 dB - 2 hours
- 110 dB - 30 min
- 120 dB - 7.5 min
Pump up the volume?
One of the most amazing facts about life on earth is its ability to adapt to different environments. If you ease your self into a hot bath you will find that you get used to the heat over five minutes or so. The same applies to your ears, if you get used to the current volume level you may find yourself turning it up, then turning it up again, and again, until you have no more to go.
Take note of the following warning signs. After exposure to loud music or noise you may experience:
- Ringing or buzzing in the ears
- Slight muffling of sounds
- Difficulty in understanding speech. You can hear all the words, but you can't understand them.
- Difficulty in hearing conversation in groups of people when there is background noise
- Difficulty in hearing conversation in groups of people in rooms with poor acoustics.
If you experience any of these early warnings, don't wait to seek help. Have your hearing checked by an audiologist, or have your ears examined by an ear specialist. Protect your hearing by wearing ear plugs or turning down the volume. Take breaks. Give your ears a chance to recover.
So how loud is the Apple iPod?
The federal government does not require manufacturers to provide information to consumers with regards to maximum loudness, and for that reason you wont get any exact figures from Apple. Recent tests have shown iPods and similar devices have lower maximum levels than devices made in the 1980's and 1990's. this is probably thanks to greater public awareness. Still, most modern mp3 players can hit 100 decibels (the noise volume of a chainsaw; risk of hearing damage after two hours) but not higher than 115 decibels (a football game in a loud stadium; risk of hearing damage after 15 minutes),
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