Although they are defined by the centre band frequency, the filter characteristics are quite broad and internationally standardised. An octave filter effectively attenuates frequencies which are greater than 1.414 and less than 0.707 of the centre frequency (eg the 2kHz filter stretches from 1.41kHz to 2.82kHz).

Noise Control - Octave band measurements are most often performed with an unweighted filter network, ie Z (or Linear), so that the distribution of the energy source can be assessed. Although the work in the noise control field is often best left to the specialist, as noise control measures may involve treating multiple noise sources, each exhibits complex modes of vibration.