I've now for the second time encountered a multiplayer match where there was a constant background noise. The first time I thought someone was just messing around and played some sound effect via his microphone, but I now encountered exactly the same sound effect a second time.
The effect is pretty much audible the whole match, it's not a constant hum but an oscillating one, and it's very annoying.
What causes this annoying sound and how do I make sure I don't encounter it a third time?
