I'd guess the full range option is likely best for clarity and dynamic range, while the nighttime option is better for playing at lower, leveled volume levels without losing the quieter sounds in the mix. I use this when playing music and leveling the game audio with it for a good overall balance without drowning out one or the other.
Either way though, and regardless of the in-game mix I use, the game sounds like... hmm... imagine a large sheet of metal as a speaker muffled by a blanket.