I suspect that prolonged exposure to a humongous woofer in the trunk might still get to you! (Mike, I hope you're a good sport, because, you gotta admit, that thing of yours is a bit extreme! :)

What causes hearing damage? Are the finer cilia torn off by a sudden peak?

I bought a sound pressure meter from RS a few months ago when I started getting interested in Acoustics (largely because of these discussions), and I was interested to find that if the spl is 100db near my speakers, that is more than enough for me sitting at my couch. (My speakers can go much louder than that.) I was also interested to do a sweep with a signal generator and find out that there is a fair amount of sound at frequencies that I cannot even hear. If a tree falls in the forest, and nobody hears it, can it still make you deaf? :)