Does anyone know if wearing over-ear headphones (eg: MDR-7509's) for many hours a day can induce hearing loss over time?
Not playing music, just editing voice files.
Playback volume not excessive just constant aural detachment from the outside world.
Not sure if hearing sensitivity might be at stake?
There's no inherent risk in prolonged use of headphones provided the volume is kept at reasonable levels (at least according to my otorhinolaryngologist).
Aural isolation is not a problem, on the contrary, the protection from environmental noise provides a rest to the ears that can be beneficial.
Another thing is the tiredness caused by intensive concentration when editing audio, searching for cues, etc. As I understand this is more a mental thing, not a physical one in the hearing aparatus (again, if volumes are kept at confortable level).
Yet another concern is the disconfort caused by using the headphones for long periods of time (skin irritation, hot ears, etc.). If you're planning on many consecutive hours of usage, confort is as much a concern as audio quality (but again, this has nothing to do with loss of hearing risk).
If you keep under the safety limits in your listening levels and time exposed and take breaks from listening (I've heard 15 minutes break per 45 minutes of listening), then I think you should be safe.
Notice that ear fatigue can lead to having to raise levels in order to get the same listening sensations. That's an alarm for that you should take a break. Some put a mark on their volume controls that they can see, whether they've crossed it.
