Second in the series of 128 tests Reply #25 – 2002-01-14 09:17:34 In biological systems, I suppose it is possible to get unusual sensitivities, freak performances and critical failings. I have read of a human hearing defect where a person hears a different pitch in each ear: to use that subject to develop an audio coding system wouldn't be useful.It is more useful to look at attributes and responses that can be categorised as standard subject response. To do otherwise would be to study atypical human perception and disease. For developing perceptual audio coding systems, one should be able to identify & categorise artifacts that "typical" listeners will recognise and dislike. I think that ff123 has identified that most of his listening group responded in a similar fashion to the artifacts produced by the codecs. This must represent the standard response to artefacts by the human ear/brain system. There will be some that respond differently, but they would be better pulled from the testing group on the basis of outlier performance.