dave wrote:

64K mono would be about as crystal clear as 128 stereo, no? That's
crystal clear to most people. I listen to 32 K web streams which are
great for all but most critical applications.

I think Tony forgot to mention that DAB uses the mp2 codec, which is
*very* in-efficient compared to modern codecs.

At 128k in stereo, the sound quality is not much better than aac+ at 32k
in stereo. So I would expect aac+ 32k in mono to sound significantly
better than mp2 64k in mono.

Richard E.