How to Replace Minecraft Sounds with Your Own! Full Tutorial
Use a tool like Audacity or an online converter to change killaura_hitsound.wav into an .ogg format. killaura_hitsound.wav
Rename your converted killaura_hitsound.ogg to match the vanilla file name (like hurt1.ogg or hurt2.ogg ) and place it in the corresponding folder. How to Replace Minecraft Sounds with Your Own