I was told by an audioligist some time ago, that NASA commissioned a study to find out why the astronauts had a difficult time hearing command even though their headsets were at a very high level. THAT was the problem.
Someone, apparently not an audiologist, thought that for the astonauts to be able to hear Mission Control above the den of noise inside the spacecraft, that the 'phones' would have to be at a high level. That wasn't true, because as their study showed, the ears begin to shut down with extreme volumes. I am going on memory so this won't be right, but it went something like this.
The study showed that:
After continual 80 db virtually no loss
85 db neglible loss across the audio spectrum,
90 2/3db after 15 minutes,
95 6 db after 15 minutes
100 >6db, and so on.
So the result was, that their 'turning up the volume' had the inverse effect of helping, and in fact shut down the pilot's ears.
This information may be useful to audiophiles. The next time you begin listening, start at a lower volume, because, you're working against physiology by starting out too loud, it only serves to 'shut your ears down'.
Hope this helps someone.
Someone, apparently not an audiologist, thought that for the astonauts to be able to hear Mission Control above the den of noise inside the spacecraft, that the 'phones' would have to be at a high level. That wasn't true, because as their study showed, the ears begin to shut down with extreme volumes. I am going on memory so this won't be right, but it went something like this.
The study showed that:
After continual 80 db virtually no loss
85 db neglible loss across the audio spectrum,
90 2/3db after 15 minutes,
95 6 db after 15 minutes
100 >6db, and so on.
So the result was, that their 'turning up the volume' had the inverse effect of helping, and in fact shut down the pilot's ears.
This information may be useful to audiophiles. The next time you begin listening, start at a lower volume, because, you're working against physiology by starting out too loud, it only serves to 'shut your ears down'.
Hope this helps someone.