Hi murph and all,
"Ultra-trained ears" signing in here, ha, ha. Actually, in the very controlled double-blind listening tests of compression codecs that took place in Ottawa (where I was on the listening panel) and which were repeated in the U.K. and Australia with similar panels of trained listeners, we found 320 kbps to be "essentially transparent" for virtually all but the most complex types of music.
The exceptions were test tracks that had castinets; also a harpsicord selection and a solo vocal a cappella by Suzanne Vega. Those anomalies were only audible with intense comparisons using headphones--we really couldn't reliably detect them with loudspeaker playback. By the way, the listening sessions went on for several days, plus a day of training, so the results, which were replicated by the Australian and UK listeners, are extremely reliable.
The harpsicord sounded a bit harder, more metallic, and Suzanne Vega's solo voice became a bit sibilant and harder sounding. The castinets took on a slightly metallic sound. The rest of the music including rock, classical and jazz, sailed through at 320 kbps with no audible anomalies.
Regards,
Alan (UTE)
