It's sort of bonkers that we've quietly gotten to the point that codecs for music are getting compared at the 32 kbps level, for full stereo. Audiophiles used to constantly be making comparisons between codecs to see what's superior, but that whole field seems to have died when Opus became very difficult to ABX at 128 kbps. There hasn't been a HydrogenAudio multiformat test in nearly a decade [1], and that one was 96 kbps.

These days even YouTube videos get transcoded to 128 kbps Opus, which is astonishing. Provided that the source is high enough quality, you can listen to transparent audio on the lowest-tier streaming platform.

[1] https://wiki.hydrogenaud.io/index.php?title=Hydrogenaudio_Li...

>Looks like xHE-AAC beats opus on <32 kbps/s

to be fair that tester indicated only voice being ok, and everything else just bearable under condition you are consciously working under severe bw constrain "EDGE poor network is still enough to stream music without issue (in a tunnel, on mountain…)"

Yeah, opus is incredible for speech, but at those bitrates it gives music a kind of sibilant buzzing that's really hard to listen to, whereas (I find) the muffled/underwater effect of mp3 and aac isn't much worse than just lowpassing.

What I found was that explicitly lowpassing beforehand to match the other encoders (around 4-8kHz) got rid of the buzzing. Apparently opus' threshold for automatically doing this is a lot lower than the other encoders; it keeps higher frequencies at the cost of more artifacts. I concluded that decimating or setting the bandwidth to 8kHz/"wideband" or lower was an improvement, and similar to the others, though I still slightly preferred Fraunhofer at 8-24kbps.

By default, 12k and 24k are particularly bad; at 16k the quality goes up from downmixing to mono, and by 8k decimation is automatically applied.