Audiofiles: For normal (= wired) headphones, I personally don't worry at all. That's comparatively low frequeny and energy radiation (= on my personal danger scale that would equal a warm summer breeze
). If one would have to worry about that, electric shavers, hairdryers et cetera would be much more dangerous. I'm not worried about Bluetooth, either - same goes for anything in that radiation class with fast frequency hopping: Even if it's around the resonance frequency of certain molecules, it's still very low energy - and the fast frequency hopping should more or less prevent resonance, anyway. I might be rather worried, if I had to live very close to military radar stations, for example - but otherwise I feel pretty save about most consumer electric devices. Amateur radio stuff is a bit more dangerous, but, at least over here, you have to learn quite a bit to get the license, so a radio amateur usually knows that a 200 W ukw sender with a parabolic antenna is not the thing one'd want to stand directly before, when it's in operation...
In other words, there are a lot of parameters that have influence on the danger potential of electric devices. And as usual with technology, the more one understands about the stuff, the better one can estimate potential dangers.
Greetings from Hannover!
Manfred / lini
P.S.: Oh, I forgot: With dynamic headphones (are/were there magnetostatic ones, btw?), there's also that permanent magnetic field issue. Oh, well... I guess, that's another summer breeze on my danger scale.
P.P.S.: Got to confess, that I'm not so sure about some other technologies there: I haven't been really worried about 900 MHz GSM and our analogue wireless phones over here - not so sure about 1900 MHz GSM and DECT. The fact, that two of my friend who are or have been into mobile phone development both aren't so sure about 1900 MHz GSM and DECT as well as 802.11x WLAN, doesn't comfort me, either.