Crackly sound

Hi folks,
my copy of Master Chief collection has developed a weird sound fault; it seems to have gone very crackly and distorted? I just finished Halo 3 and it was working ok. I started a new campaign on Halo 4 and the sound (music and everything) has gone crackly and distorted. I have tried switching off and restarting, and also starting a fresh game of Halo 2, but nothing seems to make a difference. The sound is fine on the TV. Any ideas on a fix?
thanks

Does it happen also in online matches or in other games that are not mcc?
If you have this problem also in other games I would say it is cause by your xbox or a cable.
if it is only related to mcc I suggest you to disinstall and reinstall: if it persists it may be a cd problem

Thanks for your suggestions- I really appreciate it. I managed to solve the problem via a slow process of elimination. It was actually a fault with my A/V receiver, which had weirdly developed a problem processing 5.1 sound (but not stereo), on some channels only! (The TV sound was fine, but blu-Ray and Xbox were distorted, but not all the time!). A firmware update seems to have resolved the problem (hopefully permanently!).