"John Atkinson" wrote in message
om

Unfortunately yes. But two excellent papers by Earl Geddes and his
wife, presented at the recent AES Convention, show a way forward, by
looking at how the spuriae produced by the "bent" transfer function
of a typical amplifier can be examined using a masking model
representing human perception. Their provisional results show
excellent correlation between the metric for a given amplifier and
the audibility of its spuriae.

Geddes' specialty is loudspeaker design and evaluation. Therefore he's
concerned with relatively high levels of distortion by the standards of
modern audio power amplifiers.