i don't think there's a certain db level you "instantly" lose your hearing at as far as car audio go's. over a long time at high levels is what causes you to lose hearing, so the louder level you play it at the faster it'll go.
Also how do they measure DB with a metter of w/e?
not sure what that^^ means. you mean a termlab, the meter they use at comps?
and i would say 140db in a daily driver is respectable.
Hmmmmm, I am probably twice the age of most guys here, been into stereos since 1984 and been a truck driver for a very long time too. Ya I have lost a lot of hearing, so has my wife from being a flight attendant, the planes are loud. It is funny I have lost some hearing at a certain frequency but I can hear bass from a mile and I notice the high pitch of a tv power supply from upstairs when my son accidentally leaves it on but when people talk to me, forget it I just don't hear them, lol. Polo..
I've had my stuff in for a few months now and haven't noticed much of anything. I've done more damage to myself and my car than my hearing. I believe my bass rattled my rear left window off the regulator so now it doesn't go up/down, I broke my rear view mirror trying to hit it to stop it from vibrating, and I removed my rear top brake light since it rumbled a ton. But my hearing is great. I can walk into my house and tell if a TV is on because I can hear the high pitched whines they make... I'm also about 1/2 as young as Polo so I figure I have some time :D