Jond,
The extent to which Flac can compress does depend a lot on the type of music and the recording. The BBC broadcast was classical music (the Proms) with a great dynamic range. That allows far more compression than pop music mastered loudly.
Are you sure you can still distinguish if you do the comparison double blind? Try one of those websites with streams at different bitrates that you cannot know when you listen. The statistics show that people score not or hardly better than random when trying to identify 320 kbs from full redbook CD. You may have better hearing than that, but to be sure the test has to be double blind.
The extent to which Flac can compress does depend a lot on the type of music and the recording. The BBC broadcast was classical music (the Proms) with a great dynamic range. That allows far more compression than pop music mastered loudly.
Are you sure you can still distinguish if you do the comparison double blind? Try one of those websites with streams at different bitrates that you cannot know when you listen. The statistics show that people score not or hardly better than random when trying to identify 320 kbs from full redbook CD. You may have better hearing than that, but to be sure the test has to be double blind.