FWIW, mono at32kbit/sec is fairly close to stereo at 64. (Of course, there is some joint coding gain from stereo— but stereo's wost case is just as bad as 2x mo

FWIW, mono at32kbit/sec is fairly close to stereo at 64. (Of course, there is some joint coding gain from stereo— but stereo's wost case is just as bad as 2x mono and it's the often the worst cases that limit the quality). For example, mono speech at 32kbit/sec: https://people.xiph.org/~greg/celt/spec.orig.wav https://people.xiph.org/~greg/celt/spec.orig.wav https://people.xiph.org/~greg/celt/spec.MP3.wav https://people.xiph.org/~greg/celt/spec.MP3.wav https://people.xiph.org/~greg/celt/spec.vorbis.wav https://people.xiph.org/~greg/celt/spec.vorbis.wav https://people.xiph.org/~greg/celt/spec.CELT.wav https://people.xiph.org/~greg/celt/spec.CELT.wav The SILK+CELT hybrid does better still, but even CELT alone is still fairly useful at lower rates.