Present Usage of 468-weighting
468-weighting is also used in weighted distortion measurement at 1 kHz. Weighting the distortion residue after removal of the fundamental emphasises high-order harmonics, but only up to 10 kHz or so where the ears response falls off. This results in a single measurement (sometimes called distortion residue measurement) which has been claimed to correspond well with subjective effect even for power amplifiers where crossover distortion is known to be far more audible than normal THD(Total harmonic distortion) measurements would suggest.
468-weighting is still demanded by the BBC and many other broadcasters, with increasing awareness of its existence and the fact that it is more valid on random noise where pure tones do not exist.
Often both A-weighted and 468-weighted figures are quoted for noise, especially in microphone specifications.
Read more about this topic: ITU-R 468 Noise Weighting
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