This Recommendation applies to band filters commonly known as octave, half-octave and third-octave band filters of the passive or active type, the latter including amplifier elements, e.g. tubes, valves and/or transistors.
It specifies the most important characteristics of these filters together with the corresponding tolerances.
SIS SS IEC 225:1985 history
1985SIS SS IEC 225:1985 Acoustics - Octave, half-octave and third-octave band filters intended for the analysis of sounds and vibrations