Na wat zoekwerk kwam ik dit ( Engelstalige ) stukje tegen,
waarin de eerdere beweringen weer worden tegen gesproken:
[quote:9ee7f2750b][b:9ee7f2750b]Air Tight Seal - does it create too much pressure?[/b:9ee7f2750b]
So, if it’s true that ear canal earphone form an “air-tight seal” then surely no matter what level the volume is the pressure between the earphone and the ear membrane has nowhere to release itself and is, therefore, dangerous to the fragile ear membrane?
No, not at all. Your eardrum experiences pressure differences all the time - that’s how it works! When a sound wave hits your eardrum, it causes a momentary increase in air pressure on that side of the eardrum, which causes the eardrum to move and the volume of the sound you hear is proportional to the pressure. Your eardrum can’t tell whether the pressure it experiences is due to a speaker 3 metres away or an earphone transducer 1cm away, and it doesn’t really matter - the only real difference is that the transducer is only having to move a very small volume of air to get the same effect as the speaker moving a very large volume of air.
If you were to seal a full size bass driver in an airtight seal to your eardrum and turn that on then yes, you could massively over pressurise the eardrum - but the miniature transducer in an ear canal earphone only m[/quote:9ee7f2750b]