While the old nether music tracks by C418 can play generically in-game while the player is in the nether, they aren't actually possible to hear via the /playsound command. Playing music via the available nether sound events will always result in the biome-specific tracks by Lena Raine being played.
For example, using commands to play nether wastes music (/playsound minecraft:music.nether.nether_wastes music @s ~ ~ ~) always plays "Rubedo". If it's intentional that these events only play the biome-specific tracks, then there should be a generic _music.nether sound event added for the other tracks.
Comments 4
There is no confirmation that the issue I've mentioned is intentional behaviour in the first place. Please re-open the issue.
This might actually be a resource pack issue. After disabling my resource pack (one which only changes textures, I should mention) I was immediately able to get a C418 track to play through /playsound. Either that, or I've just been very unlucky before this. I'd have to test a little more.
Apparently I was just getting very unlucky when testing this issue. For whatever reason in 20 attempts I hadn't encountered anything other than the new tracks when using the command, but now after a few attempts I'm able to get the old tracks to play.
This is a feature request. You can add these events yourself with a simple resource pack