The audio for Minecraft sounds low quality, echoey, and has a large amount of white noise in the background of the audio. It does not do this on Windows 10 edition and I have confirmed it sounds the same when wearing different headphones. I have reinstalled the launcher and deleted my Minecraft files as well, to no avail. This happened completely randomly one day.

Notice how the button presses have extra reverb in the first video.
In the second, the portal sound effect has too much reverb and the grass is too gravely.
The third video shows the Windows 10 edition of the portal entrance sound effects. These sounds are normal.