I tried it using the build from your site. It was the same result. When I adjust the volume using the slider while using the AudioStreamPlayer2D, it's sometimes noisy, making crackling sounds. It's not terrible, but noticeable, making a game not seem very professional. When I switched it to use the AudioStreamPlayer, there was no crackling noise when using the slider, regardless of how aggressive I'd slide it. It's also louder, which I like.