Loud noise kills ears!
You have touched on a number of issues.
Originally Posted by STHLS5
First, yes, there is no doubt that if you expose yourself to loud sounds, all the evidence is that you do destroy your hearing. Whether that destruction occurs over years and decades or after one night at the rock concert* depends on many factors. So please, do not think that you can get away with exposure because you can't! Your ears, like a car odometer, clock-up evidence the lifetime of use and abuse. And those in the WHO who have studied loudness exposure lay-down a recommendation that long term exposure should be limited to 85dB to preserve hearing. But that does not means 85dB is safe.
The other factor experts report on is the spectral content of the loud sound. If, as you have observed, the spectrum is like hiss (actually wave sound will be more like pink noise than white noise hiss) with most of the energy in the low frequencies and progressively less in the highs, then the ear is better protected. The fast way to destroy your hearing is to work in a factory on a repetitive job which has the combination of loud, high pressure steam (white noise, lots of high frequency energy), hammering of metal on metal (impuslive sound, lots of HF energy) and a drone or whistle from some machinery. Analysis of such damaged ears show a generally low sensitivity to normal sound plus a hole in the frequency response where the whistle has literally killed the sensory hairs at that physical place along the organ of hearing. I myself have a small notch in my right ear's response which appeared between hearing tests a few years ago followed by a quick recovery to normal beyond that. How it occurred and why it occurred is a mystery as I have always been extremely careful about loud sounds around me. But it's there, and it has no sinister cause and is sufficiently high-up the scale that it has no effect on listening. So be careful!
*As I mentioned previously, the audiologist told me that his previous patient was a 17 year old girl who had been in the front row of a pop concert next to the PA speakers. That one evening's exposure had completely destroyed her hearing. She had zero hearing acuity, hence there was nothing he could do for her. She will spend the rest of here life as profoundly deaf.
P.S. I can make a very convincing surf sound by taking a computer generated pink noise signal and modulating it with a slow-moving wave to give it the ebb and flow effect. I could have saved you the bother of taking a vacation altogether!
Alan A. Shaw
Harbeth Audio UK