![]() ![]() Other than physical damage to the actual hearing mechanisms of the ear, unwanted noise or sound can induce stress and may hinder concentration. Exposure to noise can be more damaging than you may realise with the most obvious and severe result being deafness. The word NOISE refers to unwanted and unpleasant sound. Noise disturbances are a large part of the service we offer, ranging from domestic complaints to large-scale acoustic planning. the sound level that would be expected if the noise disturbance wasn't present. The LA90 is used to give an accurate approximation to the background noise level, i.e. More specifically, it shows the equivalent amount of energy in a given period for a fluctuating source as if it were a steady continuous noise level. ![]() The LAeq is essentially an average noise level. The LAmax shows the highest noise level reached in a given time period. The ‘A’ in all of these parameters refers to the use of the A weighting scale. With reference to the graph on the About Noise Services page, you will see that the y-axis is labelled as dB(A) and contains data for LAmax, LAeq and LA90 levels. The results of these calculations form the A weighting scale as shown graphically at the bottom of the page. This means that a low frequency sound of equal decibel level to a higher frequency sound will appear to be quieter.Ī-weighting To reflect the ears differing sensitivity to frequency, when measuring sound in decibels a deduction is applied to certain frequencies. Of key importance is how loud the noise is however, the frequency of the noise and length of time to which the ear is exposed to the noise will also contribute.įrequency The ear is more sensitive to higher frequency sounds than lower. The physical effect of noise on the ear varies greatly depending on many factors. Measuring the ears response to sound on a linear scale would involve a scale ranging from 0.000001 to 200 compared with a decibel range of 0 to 140. Sound is measured on a logarithmic scale because the range of sound levels perceived by the human ear is so vast. Similarly, for a noise level to increase by 1dB the intensity must increase by a factor of 1.26. This means that if a sound doubles in intensity, rather than a doubling in decibel level a 3dB increase will be observed. Decibels are units on a logarithmic scale. ![]()
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