Blake, welcome. One point to keep in mind is that the frequency response curves are often measured in an anechoic chamber(rather than a room)which, depending on its size, doesn't give accurate results below about 80-90Hz. So, don't attempt to use those graphs to judge the low bass under 100Hz, since it will vary significantly when in-room reinforcement is present.
As has been mentioned, 80dB is actually a fairly loud level(ordinary conversation is maybe 60-65dB), and is about what I refer to as "comfortably loud". Even quiet rooms at home would have a background noise level of at least 40dB, so music would have to be louder than that to be even audible above the background.
