The Twilight Forest sound fixes
Most likely due to an oversight by the developers, many creature sounds in the Twilight Forest modification were recorded in mono format instead of stereo, which completely destroys the perception of positional sound in the game.
Because of this issue, some sounds such as bird singing or crow cawing get overwhelmed by random noises that theoretically shouldn't be audible. For example, you might hear a deer sound as if it's right next to the player, when in reality it's two chunks away.
For a better understanding of the difference, watch the short video below.
Important: Some mobs actually should produce sounds in mono format, such as cicadas and deer, so I only changed what truly required correction. I don't add or remove any sounds from the original modification.