A spl measure next to a transducer is a bit simplistic. The control volume that makes up a reverberant field is another... a pair of cans hugging/sealing a very small control volume (such as the ear canal) leaves very little room for error.
There are also countless types of sonic 'impulses'...in nature, instruments, urban areas, industrial environments, etc...they all don't affect the ear the same way...an spl meter alone is not the ultimate guide.
@larsman wrote
@deep_333 - I've got a headphone system in addition to a 2-channel one, and there's no reason headphones should cause any more hearing damage than speakers. Blast 'em over long periods and you can damage your hearing. Don't and you should be good. Isn't 80db 80db no matter the transducer?
Large venues with bad PA's and high distortion that leave your ears ringing afterwards 100% can damage your hearing.

