Other terms commonly found in acoustics

As an approximation, it is commonly accepted that an increase in sormd pressure level of 8-10 dB corresponds to a subjective doubling of loudness. There are a number of different ways of calculating the loudness, and the loudness level in phon should be referenced to the method used. 

It is apparent that the subjective response to noise is extremely complex and these complexities should always be borne in mind when dealing with individual people. A noise or noise level which is acceptable to one individual may not be to another. 

The previous two sections have not attempted to define frequency in terms of a bandwidth. The generally accepted bandwidth used within the field of noise control are octave bands, that is a range or band of frequencies with the upper frequency limit/ equal to twice the lower limit/ . Each octave band is defined by the centre frequency/ob where 

Octave band centre frequency (f) Hz Octave band range Hz 

The commonly used octave bands are illustrated in Table 3.5.1. 

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