This reminds me of the time I was in an airsoft firing range with one of the local snipers. He was busy zeroing his scope so I casually asked him if I could shoot some targets beside him. His rifle was practically inaudiable so I guess he was used to that sound level. My GBB on the other hand, for one reason or another, is one the loudest things I've found in airsoft. In any case, while I emptied my mag into a target (I was testing the piston head on my GBB) he practically jumped out of his boots.
Long story, short: Sound levels are subjective so, as Greylocks repeatedly states, go out to a game to get an idea of the range of noise.