I'll try to post some tech data I've read recently, at a later time. The post by Sleepy was good.
The good thing about gunshots is that it is a "pulsed" sound. Far less damaging than a constant high-level noise. Imagine a candle flame... feels hotter the longer you let your hand linger over it, even tho the temp's the same. If you just pass your hand thru quickly, it doesn't seem that hot. Sound is sorta the same, I'm told.
I wear electronic muffs, with foam plugs in addition. With the volume turned up, I can hear all range commands. Recently, I was glad I did... I was executing a stage in an IDPA match, and right in the string of fire, while on the move, my headset fell off. Because I had foam plugs too, I kept right on shooting with just a slight distraction and no discomfort.
Double plugging has another advantage... the muffs protect you to a greater degree from the sound vibration that is transmitted through the ear/face bones, whereas plugs alone don't.
The constant barrage of noise pollution we are all exposed to on a daily basis is also alarming (to health professionals too), and many don't seem to even notice. I've been to concerts where people stand right next to the speaker towers going full blast, for hours. I know the sSP levels must be over 120dB. Crazy. When a fire truck goes by on the street, I plug my ears, and notice that most others don't. I guess I have too much $$ invested in hi-fi gear to be totally careless with my hearing. I always keep a couple pairs of the cheap foam plugs handy. -more-
Good LINKS page: [URL}http://www.pp.okstate.edu/ehs/links/noise.htm[/URL]
Sound is measured in decibels (dB). The scale runs from the faintest sound the human ear can detect, labeled 0 dB, to the scream of a jet engine or a shotgun blast at over 165 dB.
Exposure to more than 90 decibels for eight hours a day (the noise level at a loud party) may be dangerous to your hearing. In addition, there is a trade-off between time and intensity: at 95 dB (the noise level of a loud portable stereo or a dirt bike) the same damage can result in four hours. At 100 dB (the noise level of a chain saw) it takes just two hours to do the same damage to your hearing.
"It doesn't matter what the source of the loud sound is," he added. "If it is loud enough and you are exposed long enough, hearing loss will result."
Extremely loud noises, like gun shots, or even firecrackers or cap pistols, can cause immediate damage. "Anyone using firearms without ear protection risks serious hearing loss," said Gates. To protect your hearing, turn down the volume on the stereo headphones, and wear ear protection when noise is unavoidable, whether from a power lawnmower or a rock concert. Some rock musicians are even wearing earplugs to protect themselves from their own music.
Hearing specialists recommend earplugs or earmuffs for anyone who works (or plays) in a noisy environment. Snugly fitted earplugs can provide from 15 to 30 decibels of noise protection, while snug-fitting earmuffs offer even more noise reduction. Ordinary cotton is too porous to provide any protection. It's important to realize you can be damaging your hearing without even knowing it, said Gates, because the loss is at first subtle. Often the first symptom is a ringing or other sound in your ear (tinnitus). Or you may have trouble understanding what people say; they may seem to be mumbling.
The high frequencies are lost first, so you may have difficulty hearing high-pitched voices. Loss of high-frequency hearing makes many words sound alike, especially those containing the high-frequency sounds S or soft C, F, SH, CH or H. Words like "hill," "fill" and "sill" may sound exactly the same.
from
http://www.nonoise.org/library/suter/suter.htm#impulse
http://www.nonoise.org/
5. Varying and intermittent noise
Investigations of the relationship between noise level and duration have been conducted over recent years using laboratory animals. The results have confirmed the validity of the equal energy (3-dB) rule for single exposures to continuous noise (Bohne and Pearse, 1982; Ward and Turner, 1982), or when the exposures are broken up into 8-hour, or even 1-hour "workdays", 5 days per week, so long as the sound energy is equivalent (Ward, 1983). There is, however, some benefit to intermittent quiet periods (Ward and Turner, 1982), during which the ear can recover from small, temporary hearing losses.
6. Impulse noise
The effects of impulse noise have been studied extensively over recent years, but there is less agreement on this topic than there is for continuous and intermittent noise.
Frequency also has some bearing on the damage caused by impulse noise, in that low-frequency impulses produce significantly less damage than sounds in the mid-to-high-frequency range (Price, 1983). The ear appears to be most susceptible to impulses with peaks around 4,000 Hz (Price, 1989). Also, there may be a critical level, above which the ear is considerably more at risk because of a change in the response mechanism. On the basis of his research, Price (1981) has suggested a critical level of 145 dB, with a standard deviation of 8 dB.
Loud music in particular appears to be the cause of hearing impairment and tinnitus in rock musicians. Such luminaries as Pete Townshend and Ted Nugent (8) have acquired substantial hearing losses and are now campaigning for hearing conservation (Murphy, 1989). Some studies point to a hearing hazard for attendees as well
As mentioned above, probably the greatest nonoccupational hazard to hearing comes from
sport shooting. Clark (1991) cites studies of industrial workers by Chung et al. (1981), Johnson and Riffle (1982), and Prosser et al. (1988), showing significantly greater hearing losses among sport-shooters than among their nonshooting counterparts. These losses are almost always characterized by worse hearing in the left ear than the right.
[This message has been edited by Covert Mission (edited November 29, 1999).]
[This message has been edited by Covert Mission (edited December 03, 1999).]