1.20.1 Forge 47.4.0
Ambient Sounds 6.1.11

Ambient does not play in cave biomes from mods such as Galosphere, Regions Unexplored and Yung's Caves Biomes

Sorry, but 1.20.1 is not supported anymore. If this issue persists in newer versions make sure to post a few screenshots with /ambient-debug enabled, so I can figure out what is going wrong.

@CreativeMD
Reproducible on Neoforge 1.21.1
AmbientSounds v6.2.2
Galosphere is not available on this version, but all cave biomes from Regions Unexplored and Yung's Caves still don't have ambient

These underground biomes are difficult to support, because they depend on custom blocks.

In order for AmbientSounds to detect cave sounds correctly it checks if rock is around. These mods add new blocks, which means there is not enough "rock" for a cave sound to play.

This can be fixed if these new blocks are considered rocks. There is a tag from minecraft, unfortunately these mods do not add their blocks to it. If you want to you can send me the names of these blocks (I need to know the registry name, which is visible if F3 enabled when looking at the block or via F3 + H in inventory).