well documented by who where with what credentials - Still citing yourself
I
see?
A quick medline search brings up several relevant references to support what
I said in the preceding post...
Levine S. Hofstetter P. Zheng XY. Henderson D. Duration and peak level as
co-factors in hearing loss from exposure to impact noise. [Journal Article]
Scandinavian Audiology. Supplementum. 48:27-36, 1998.
Cochlear damage caused by continuous and intermittent noise exposure,
Hearing Research, Volume 178, Issues 1-2, April 2003, Pages 70-78
Akram Pourbakht and Tatsuya Yamasoba
Temporary and permanent noise-induced changes in distortion product
otoacoustic emissions in CBA/CaJ mice, Hearing Research, Volume 156, Issues
1-2, June 2001, Pages 31-43
Ana E. Vázquez, Anne E. Luebke, Glen K. Martin and Brenda L. Lonsbury-Martin
The effects of interrupted noise exposures on the noise-damaged cochlea,
Hearing Research, Volume 143, Issues 1-2, May 2000, Pages 103-109
William A. Ahroon and Roger P. Hamernik
Noise-induced hearing loss in the noise-toughened auditory system, Hearing
Research, Volume 129, Issues 1-2, March 1999, Pages 101-110
William A. Ahroon and Roger P. Hamernik
Reduced temporary and permanent hearing losses with multiple tone exposures,
Hearing Research, Volume 6, Issue 3, April 1982, Pages 291-301
A. R. Cody and B. M. Johnstone
Oftedal G. Nivison ME. Jinze Z. Intensity-time tradeoff for constant hearing
loss with high sound levels. [Journal Article] Journal of the Acoustical
Society of America. 83(1):203-11, 1988 Jan.
Compensation in over-stimulation is detailed in Hudspeth's recent work. I
don't have any exact papers handy, but I can find them.
And the abstract on this one was interesting...
Ramsey KL. Simmons FB. High-powered automobile stereos. [Journal Article]
Otolaryngology - Head & Neck Surgery. 109(1):108-10, 1993 Jul.
"We measured the owner-adjusted acoustic outputs of 10 automobile stereo
systems, with power ratings ranging between 150 and 600 watts. The sound
levels ranged from 107 to 138 dB SPL and 84 to 108 dBA. Most of the
high-intensity sound was in the 31, 62, and 125 Hz center-frequency octave
bands. The mean computed noise dose, based on the vehicle owners' reported
daily duration of exposure, was 108.5%. While there is clearly a risk of
hearing damage in the extreme cases according to OSHA standards, the typical
listening durations claimed by the stereo owners would seem to lower the
risk for the majority to acceptable margins for the automobiles measured."
"Mark Zarella" seesigfile wrote in message
news
Furthermore, it's been well-documented that there are two chief
variables
with regard to noise-induced hearing loss: an intensity variable and a
time-domain variable. It's also been well-documented that the
relationship
between these and the energy of the stimulus is highly nonlinear. The
values provided in the web sites he posted from are almost entirely
arbitrary and provide no worthwhile point of reference. They are
nothing
more than layperson FAQs! They're written strictly for morons who
actually
don't know that loud sounds can (can, not will) cause damage.
My contention is, and has been, that it's NOT EASY to cause permanent
damage. Does that mean that I said it's impossible? Of course not.
But
I
think it takes a complete moron to think he knows anything about the
mechanisms of hearing loss by merely reading a public service
announcement.
That sort of thing leads people to spew misinformation all over the net,
as
was the case in a recent thread here that I'll repost in hopes that
you'll
see exactly where I'm coming from. (note in particular Christina's
initial
response)
****************************
From: John Dziurlaj )
Subject: Hearing Loss in Car Audio........does it happen?
View this article only
Newsgroups: rec.audio.car
Date: 2003-05-06 17:58:38 PST
Hi There. I'm having concerns about my hearing and if my system is a
threat to it. I wouldn't say I play my system 'that' loud, maybe
pumping around 600 w (two JL 12s), but my ears have been feeling weird
as of late, and I'm just wondering if anyone in the field has noticed
any signs of hearing loss. I'm also very paranoid about things, so it
could just be that too. Any comments would be of great help! Thanks!
John Dziurlaj
***************************
Message 9 in thread
From: Mark Zarella )
Subject: Hearing Loss in Car Audio........does it happen?
View this article only
Newsgroups: rec.audio.car
Date: 2003-05-09 11:17:32 PST
I've ingnored the feeling for almost two weeks I'd say, do you think
my hearing is permently damaged?
I would go get tested. It's highly unlikely that you "lost your
hearing"
with a single exposure. What you're experiencing now I'm sure SEEMS
real,
but it actually may not be. Or it could be a symptom of a sinus or
inner
ear issue. If I were you I'd see a doctor. You won't know otherwise.
***********************************
Message 10 in thread
From: Christina Robertson )
Subject: Hearing Loss in Car Audio........does it happen?
View this article only
Newsgroups: rec.audio.car
Date: 2003-05-09 11:25:28 PST
I'd say yes you have damage. What is probalby more important than the
two weeks you've been ignoring it is how long you've been exposed to
VERY loud music in total. The effect is cummulative. Just refraining
for a few weeks and then cranking the volume back up is not a good
idea. If you're in your 20's and have been exposed to loud music a long
time you probalby already have some mild hearing loss. (It doens't have
to be heralded by any feeling at all)
The safest thing to do would be to simply turn your music down. 
Permenantly. Not only would your ears thank you years down the road,
but drivers around you wouldn't be wincing every time you went by. (Or
heaven help us get stuck at an intersection with you.) The sorts of
noises young men (though I suppose some young women also listen to VERY
loud music) play in their cars is quite often more than enough to cause
permenant and severe hearing loss over time.
Turn your music on to what seems like a good volume to you. Get out and
shut the doors. If you can still understand the words of the music its
too loud! If you can still feel that thumping base, its too loud! Turn
it down. But that's just me and I've been called an old lady.
Chris