incomplete silence
the theoretical opposite of complete silence. Silence itself is complete, yet to emphasize it the term "complete silence" is used. So, what then is the incomplete silence? It could probably be best described as an infinetly long silence with an infinetly short sound. The longer the silence and the shorter the sound the closer the moment will get to complete silence, yet it will never be perfectly silent.
someone burping during a minute of silence for a fallen soldier, that's the closest you'll get to incomplete silence in real life