The average sound exposure level may not be what you expect

We know that certain things are just taken for granted as being too loud for comfort, such as an aeroplane taking off or a rock concert, but you may be surprised that that the average sound exposure level may not be what you expect. 

The average noise dose which most people can take bear without wincing does depend on the person and what they are used to, as well as how sensitive they are to sound. For example a blind person can often hear sounds better than a seeing person because they have been trained to use that sense more. In the same way a monk who is used to silence and quiet will react differently to a noisy roomful of people than someone who has grown up in a large boisterous home where the average sound level can be quite high but are not too obvious to those who are used to it.

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit for sound pressure p is the Pascal (Pa).

Average sound levels can be measured easily and we need to decide what a comfortable level is for us. This is made easier if you have an idea as to what average sound exposure level actually is.

How loud is too loud? - Decibel level -what we hear;

·         10 dB   Normal breathing

·         20 dB  Rustling leaves, mosquito

·         30 dB  Whisper

·         40 dB  Stream, refrigerator humming

·         50-60 dB Quiet office

·         50-65 dB Normal conversation

·         60-65 dB Laughter

·         70 dB  Vacuum cleaner, hair dryer

·         75 dB  Dishwasher

·         78 dB  Washing machine

·         80 dB  Garbage disposal, city traffic noise

Prolonged exposure to any noise above 90 dB can cause gradual hearing loss, which is;

·         84 dB  Diesel truck

·         70-90 dB Recreational vehicle

·         88 dB  Subway, motorcycle

·         85-90 dB Lawnmower

·         100 dB            Train, garbage truck

·         97 dB  Newspaper press

·         98 dB  Farm tractor

Regular exposure of more than 1 minute to the following risks permanent hearing loss;

·         103 dB Jet flyover at 100 feet

·         105 dB Snowmobile

·         110 dB Jackhammer, power saw, symphony orchestra

·         120 dB Thunderclap, discotheque/boom box

·         110-125 dB Stereo

·         110-140 dB Rock concerts

·         130 dB Jet take-off, shotgun firing

·         145 dB Boom cars

SPL stands for Sound Pressure Level. It basically relates to how much acoustic energy is in sound that you hear. SPL is measured in decibels, or dB. The base reference for SPL is 0dB_SPL, which corresponds to a pressure of 0.0002 dynes per square centimetre, or about the quietest sound a young, undamaged ear can hear, between 1 kHz and 4 kHz. SPL of average sound pressure level situations are:

·         Quiet home at night = 50db

·         Average conversation = 65db

·         Heavy street traffic 5 feet away = 90db

·         Loud rock music at concert = 112db (or more)

·         Threshold of pain = 130db

·         Rifle fired 3 feet away = 140db