Frame buffering? I've had starmade for a while, and it seems only the really beefy computers (however strange it may seem) get effected by these issues. I don't know if the sound is directly tied to the FPS, although that would be a far stretch, but that could possibly be whats going on. I've never had the issue while playing so i'm completely clueless to what's going on here. You can try to search Star-made.org and post there if the problem continues.
I mean, you also could try to revert all the settings back and tinker with them 1 by 1 until the issue goes away.