Interior sound getting faded out with climb

[DLH9KA]

When climbing all my interior sounds fade out and get silent. 

Passing 15k feet there is no more air conditioning sound, no wind effect, no cockpit sounds, no engine sounds. Outside sounds are ok.

[Eddie]

Hello,

Are you able to grab me a video please? Helps us understand the issue better 🙂 

Regardless, please double check you've disabled the loudness limiter. Guide here: 

It also may be worth reinstalling the aircraft entirely.
Thank you 🙂