octave band analysis

When taking a basic noise measurement the result is expressed in db(A). This measurement includes all of the different frequencies that we can hear and is weighted to mimic the sensitivity of the human ear. However, this number alone does not tell the whole story. 

Some sounds are very low pitched (eg fog horn) or very high pitched (eg referee whistle). The db(A) figure could be the same whether the noise was predominantly low frequency or predominantly high frequency. 

In order to understand more about the frequency make up of the noise that a person is exposed to it is neccessary to carry out an Octave Band Noise analysis. With this data it is more likely that you will be able to choose the most appropriate and effective hearing protection.

See an example of an Octave Band Analysis report here <link>