You can try changing the sound quality in the options.
One person had a problem with echoes and static using headphones (speakers were fine), which disappeared if they disabled V-sync in the video options.
If the problem is the echo effect in caves, a few people have had similar issues, with a couple possible workarounds reported:
Try lowering the main system volume and in-game max all the sound sliders. That has removed the echo for some people.
Someone in the topic My sound is echo-y
said it helped if they changed the setting for the audio channels in Windows to 8, started the game, Alt-Tabbed out and changed the audio channels to 2 and switched back to the game.