Car audio help (spl dB)

Can someone explain spl,dB to me.
1. Is there a certain point of spl that can damage your ears or break glass?
2.If i get 3 audiobahn woofers and its spl adds up to 289.2 is that good?

what do u mean ur spl adds up to 289.2???
and now ur not in danger of breaking glass, maybe if u had 43 of those audiobahns but not 3 so dont worry.
oh btw any subsonic frequency's will damage ur ears, the silia is it? in your ears are pushed down by them whill listening to music then when teh music is off they do not go back to there original angle of shap... blah blah blah, basically were all going to go deaf anyways so listen and enjoy as i see it,

btw the most spl u can run in a decibel scale is in the 190's and the loudest system ever is in the high 170's with about 25 15" subwoofers and 100,000 watts of power so dont worry u dont break glass till about 162 - 165

Oh yeah believe that, you can seriously believe the loss of hearing........I have 4 15" vega's in my 1990 4 Runner and 2 1000 watt memphis's pushin em......never had a meter in there but I have most definately noticed some hearing loss my self........just low tones (go figure)..........and for the windows breakin....hmmmm never heard of it actually happening ........spose it could.....I know the seal around my front window had to be replaced from the pressure but no cracks.......but if ya get it to happen with the windows breakin be sure to get it on video....lol......I know alot of ppl would like to see that !!!!!!!

What your adding up is the efficiency of each sub, which is not SPL, nor does that have anything to do with how loud it will play. Anything over 80 dB can do damage to your hearing, as far as breaking glass that takes 160+ dB at a lower frequency (below 50 hz) and at a higher frequency closer to 167-170 dB depending on the car.

With proper design you can get low/mid 170's with only a few woofers. In my teammates car we did a 176.0 in testing on his meter legal with 6 18's and 14,400 watts.