2003-09-08 – How loud is loud?

Volume is something that affects us every day. Some mutters something, we don’t hear it. On the opposite end of the scale, if it is too loud, you don’t like it either.

My other half just phoned me on her mobile, to my mobile. Then one of the landlines rang, and I nearly dropped my mobile in reaction. To say it was loud is an understatement!

By way of pre-emptory explanation, I have just bought a digital sound level meter. For the princely sum of £50 I can tell how loud something is. This is very important to me, as I have quite sensitive hearing, due mostly to my youthful experimentation with various things, and also my long-standing ownership and useage of target firearms.

For this reason, I had no problem with checking just how loud a few things were, in every day life. For a few months now, I have been complaining about how loud the aerobic exercise class (BodyCombat) I do is. So I have now checked. Peaking at 108db, it averaged about 95db all the way through the hour.

For reference, here is the UK occupational health and safety level:

dB(A) Hours Minutes Seconds

85

8

480

Training and hearing protection must be given/offered above 85dB(A)

88

4

240

91

2

120

Above 90dB(A) hearing protection is mandatory

94

1

60

97

0.5

30

100

0.25

15

103

7.5

106

3.75

109

1.875

112

0.938

56.25

115

0.469

28.125

118

0.234

14.0

121

 

7.0

124

 

3.5

127

 

1.75

130

 

0.88

133

 

0.44

136

 

0.22

139

 

0.11

140

Never Exceed Level

You can work out your exposure here. The way it adds up is counter intuitive, but basically it is a weighted average over eight hours. That class that lasted an hour at about 100dB(A)* works out to an average of 91dB(A) over an eight hour period. This means that the instructor was breaking the law. Everyone in the class, by law, should have been wearing ear protection! In fact, anything above 85dB(A) and the instructor should be offering hearing protection to anyone who might want it. This is also the law.

Now, back to that phone call. Incredibly, the measured volume coming out of my Nokia, which for general speech was about 85dB, jumped up to an impressive 117dB(A)! I nearly dropped the phone, as it was physically painful. Of course, the problem is, the phone doesn’t boost the quiet speech elements, so it is really hard to hear the person talking clearly.

Obviously, a solution would be to bost the quiet portions of the speech dynamically, and, at the very least, damp the volume from the earpeice so it cannot exceed a set level. That way, the user could simply turn it up when in a nightclub, and have it turned down for the office.

Although problems with noise are more widely known about these days, a wearable sensor to get a good idea of the actual noise level exposure through the course of a day would be very useful. Comparisions could also be made between the noise levels we were exposed to ten or fifty years ago.

As an interesting aside, the instructor asked if 108dB(A) was loud. I said yes. She then mentioned that, at the age of perhaps 25, she is already suffering from tinnitus and deafness! Apparently, the earpeice they use feeds the voice signals back so they can hear themselves over the earsplitting music. No wonder she is going deaf in her right ear!

*The \”A\” stands for the weighting across the frequency measurement, so it ignores ultrasound and infrasound, and the response curve matches your ear – it the same way that some colours are \”brighter\” than others. My meter is set to this as default.

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