I wanted to try this mod on 1.8.9 but I noticed that sounds such as footsteps are exceptionally quiet so I'm wondering how to make them louder.

I have the same issue on Minecraft 1.16.5. I thought that the footsteps sounds didn't work because I heard nothing while walking on grass. Then walking on wooden planks made me realize that there were sounds playing but very quiet. Although, after tests, I still think that on grass, no sound is played.

EDIT: should I have open a new ticket in https://github.com/OreCruncher/DynamicSurroundings2?