Came back for me too. I wiped my sound driver again and set the video back to direct x 9... after that the sound was fine again. So everyone might want to try if the issue still exists after reinstalling the sounddriver and using the dirext x 9 instead of direct x11. (win 7 x64/Realtech HD/Razer Megadolon)
This helped me for now..
Same issue on Bajor, only appears when I walk into the plaza with the transmitter tower on Bajor. It starts and the only way to stop it is to close and restart the game, changing maps, logging out doesn't stop it. It's almost like there are too many sound channels or something.
Clean Install of Windows 7 Pro x64 - Brand new Creative Labs Recon3D with latest drivers. I've tried every combination of settings in the Recon's control panel with no effect. It's too bad, I love STO, just can't stand going to Bajor now