I also experience this issue. If it helps the developers, my soundcard is a Xonar Essence STX. My onboard sound is disabled.
HOWEVER I worked out how to fix the issue for myself. On my Xonar Control Panel, if I set the Audio Channels field to '2 channels', '4 channels' or '6 channels' the buzzing noise stops.
I originally had this set to 8 channels and have had no buzzing issues anywhere else in Star Trek Online or any other game.
To anyone trying this solution, for me when I changed the channels I had to restart the game as all the in-game audio would stop when I changed the Audio Channels setting whilst the game was running.
Also, when the buzzing noise is in effect, it seems to change as you move around the Promenade indicating it may be a particular background sound that is being distorted. I can hear other Deep Space 9 sounds above the distortion.
Logitech G35. I set foot on the station and BANG! noise. Beam out and it goes away. If I minimise the STO Window in Win7 it's still there (usually when I do that all STO sound goes). It does seem to be just certain areas of DS9 for me as well.
I have the exact same issue, sounds like the re-verb is way to high in the stations ambient. I would equate this sound to having your head in a Tesla coil, this has been going on for quite a long time now and needs to be fixed. Just to see how badly this was effecting my speakers I popped one the grills off and the speaker is vibrating like mad! This has the potential of damaging my equipment. Cryptic needs to address/fix this issue. This sound problem only seems to be present in the outer ring area / promenade of DS9.
I am using creative 7.1 surround speakers
Realtek Alc888 sound board with driver version 126.96.36.19926