130dB could be considered a "normal loud" system. this is also considered the thresh hold of pain for most people.
in other words, 130 is reasonably loud...140 will hurt if you arent used to it(everything in the car will be shaking)...150 is crazy loud (wear hearing protection or else!)...160 is, well 160 is just insane!!!
DB Amplification 0db 1 time 3db 2 times 6db 4 times 10db 10 times 20db 100 times
1db is considered the smallest audible change to the human ear. 3db is considered to be a noticeable change (like if you wanted to turn the TV volume up a tad to hear it a little better). 6-10db is percieved as twice as loud, exactly the db is hard to say as it is dependant on the persons ears, frequency referred to, etc. It is logarithmic. 100db is twice as loud as 90db, 110 is twice as loud as 100, and so forth.
"in other words, 130 is reasonably loud...140 will hurt if you arent used to it"
Only if by "used to it" you mean partially deaf. 120 dB is officially considered the threshold of pain and new studies that have been released suggest that permanent damage can occur with prolonged exposure to SPL levels over a mere 70 dB. Turns out all of the "iPodders" are going deaf.
But really, SPL in the 130's is about the average for your "everyday" systems. (ex: the guy down the street w/ 2 kicker comp 12's)
When you reach 140+ you are really starting to get loud...if the average joe sits in the vehicle they will have a hard time staying there for an extended period of time.
