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Can earplugs cause damage by making things bassy?


Izen Ears

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  I'm at a very loud concert hanging out next to the sound board, and they've got a monitor that actively displays the room dB level.  It's regularly going over 100, as high as 102.5.  Very bassy music with phat hip hop bass blasts.  You know the kind, the bass just rattles your entire rib cage, tickles your nuts, and makes your t shirt flap against your arms and stomach.

  I put in earplugs over the HN cans (with new pads) because just earplugs isn't enough.  Of course using two levels of hearing protection makes a big difference in the high and mid freqs, but it seems to increase the bass; or rather, just turn everything I hear into bass freqs.  Which is very "uncomfortable" and kinda feels like damage is occurring.  I guess it's a form of hearing pain?

  If I turn the cans up loud, I can hear the non-delayed feed I'm recording.  This sound sort of "fills in" the freqs above the bass, and is noticably less "uncomfortable" or painful.

  What's happening here?  Why would adding more sound feel more comfortable?  And The Big Question - is damage occurring when it's just bass, and very uncomfortable?  Isn't it true that 30dB earplugs don't provide 30dB of protection with sub bass freqs?

Nothing, but nothing, works better than folding that little front ear flap most of us have over an inserted earplug.  Now THAT completely eliminates the uneven freq-cutting.  All freqs sound equally softer.  Maybe gun range cans would also do this?  But I've been assuming the HN cans provide the same amount of protection.

One less-uncomfortable thing I found with this "double system" was if fold over my ears, I can place the HN cans so that they sort of hold the ears folded over.  I have kinda flexible and foldy ears, so this isn't really that uncomfortable for me, but I realize lots of people can't even bend their ears so this would prolly provide a lot of physical ear pain. 

I guess I'm sharing this in case anyone else has any methods for protection from modestly extreme sounds, without that "extra bass" effect?

  Dan Izen

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I think the absence of highs and mids will make the bass subjectively "seem" louder, but it's not really louder. Bass frequencies are much harder to trap out with traditional earplugs and head covers. I feel bad for the audience members of an event like this who are subjected to loud sounds. 

Here are the sound levels and relative time periods that OSHA believes it's safe to endure:

NIOSH-OSHA-Standards.gif

If it's 105dB, then OSHA says 1 hour. If it's all night long, I would run far away. 

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I think the lows are much more felt by your whole body than the mids and highs.  Like standing next to a car playing hip hop etc at very high levels--you can't hear any of the music but you still feel like you are being beaten up by the bass.   Earplugs don't help with that kind of thing at all of course.  This is a serious concern for, for instance, crew and cam ops who have to work in front of mains stacks and subs at big shows.

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8 hours ago, Marc Wielage said:

I think the absence of highs and mids will make the bass subjectively "seem" louder, but it's not really louder. Bass frequencies are much harder to trap out with traditional earplugs and head covers. I feel bad for the audience members of an event like this who are subjected to loud sounds. 

Here are the sound levels and relative time periods that OSHA believes it's safe to endure:

NIOSH-OSHA-Standards.gif

If it's 105dB, then OSHA says 1 hour. If it's all night long, I would run far away. 

  Love this chart!  It should be taught every single year of school, including kindergarten!  Using this chart, is it accurate to assume if one is using 30dB earplugs, that the dB levels would be 30dB lower?  As in, does fifteen minutes at 115 dB become sixteen hours at 85dB?  Seems like it doesn't, because the earplugs don't block all freqs?

Mr. Perkins - "at all?!"  Really?  As in, zero dB of protection from that sub bass crap?  So that means this uncomfortable feeling is actual damage from sub freqs?!!  With no possible means of protection?  I'll never do a music thing ever again!  I did get to see New Edition last night though!

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Glad this topic was brought up. Over the years I've worked hip hop and rock shows for news magazine style shows or for the record labels. I have often had the same experience as Dan, while wearing Remote Audio high noise cans with earplugs  as well and it still seemed like my ear drums were being violated. Hip hop style music makes judicious use of bass woofers that literally made me think I was going into cardiac arrest! I talked to the FOH engineer during a break once, and noticing that he did not wear hearing protection asked if he had any hearing problems. He said "no."

He then when on to say how he would be mixing a jazz band that was performing the next day in the same venue. I gotta think he's not hearing full range after having his ear drums blasted the night before. He's gotta be fooling himself! Bottom line I guess if you need the work,  take as many precautions on your end as possible. Don't rely on production to furnish you with anything regarding hearing protection. 

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  Okay - so there are freqs that earplugs can't tackle.  Today they started up those 40Hz (or whatever) hip hop bass blasts, I felt the attack through the plugs, and I looked over and saw the dB meter was at 86!  Only 86?!  How can this be?  It was during the sound check for Common, so at that moment it was just the bass in the air.  Only 86 dB has me thinking the dumb dB meter wasn't sensitive enough.  But then I thought, "well that thing is meant for overall sound levels, so it should be equally sensitive to, say, 20Hz - 20,000."

  Eight six decibels of a 40Hz bass blast - there's NO WAY I could take that a) for 16 hours, or B) without hearing protection.

  Some problems are relative.  So Ed, I'd say your engineer just didn't have a "problem" with the fact that he's sustained critical hearing damage!

  Alright team - time to invent all-freq earplugs!

  How about a sound-protecting helmet with built in cans?  I guess it'd have to be made out of concrete and a foot thick to start to block those subs...  Does absolutely nothing stop those?!  Solid earth?  Adamantium?

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25 minutes ago, Izen Ears said:

  Okay - so there are freqs that earplugs can't tackle.  Today they started up those 40Hz (or whatever) hip hop bass blasts, I felt the attack through the plugs, and I looked over and saw the dB meter was at 86!  Only 86?!  How can this be?  It was during the sound check for Common, so at that moment it was just the bass in the air.  Only 86 dB has me thinking the dumb dB meter wasn't sensitive enough.  But then I thought, "well that thing is meant for overall sound levels, so it should be equally sensitive to, say, 20Hz - 20,000."

 

This is probably because the Decibel meter was set to an A-weighted curve which means it is more sensitive to higher frequencies, centred around 1KHz where the ear is most sensitive.  However, the ear behaves differently to loud sounds as it does to soft sounds with the effect that at very high volumes the ear struggles to differentiate level difference between low and mid frequencies (so music will sound more bassy as volume increases).  For this reason a Decibel meter would be more accurate when set to a flatter C weighting in a concert hall.  Of course, many venues nowadays have these meters for environmental health reasons, often connected to a brick wall limiter to prevent excessive volume; by setting the meter to A-weighting you get 'more bass for your buck'.  I have worked a couple of venues where the meter will flash a warning when the max average level is exceeded and after a few minutes if the level isn't reduced, it cuts the mains power to Front of House.

In my experience, considering that sound engineers and musicians rely on their hearing for a living, they are often the worst at protecting it.  A good pair of custom made earplugs with flat-response filters are an investment you will never regret.

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Hearing loss is typically most prominent and most irritating / painful at the higher frequencies. Higher frequencies tend to get damaged faster, hence why the dBA scale is chosen for measuring SPL for regulating exposure levels. 

There doesn't seem to be as much information out there regarding low frequency hearing loss related to low frequency exposure. 

The damage is less noticable even when it has happened because higher frequency harmonics usually exist so with low frequency loss, the brain can use harmonics to discern and understand the missing low frequencies (see audio plugins like Waves MaxxBass that add harmonics to increase the perception of bass even in speakers that can't physically produce the lowest frequencies).

So, less is known about low frequency hearing loss, it's harder to detect when loss has occurred, and our measurement for regulation purposes uses a scale that is not very responsive to bass, so clubs can pump far more bass without overloading the regulating instrument (if any is being used at all!) Probably means we should tread with a bit more caution.

Also, I don't imagine proper measurement is being used in many clubs or if it is, it's being circumvented. The sound levels at a Bassnectar show I attended were unbearable. Even with earplugs, the mids and highs left my ears severely ringing and I know just from my time calibrating safe monitoring levels for post, they were far above what I'm familiar with as a safe level. 

Indoor clubs and venues are an even bigger concern. Sound levels aren't an even spread across the room. High frequencies find resonances on wall materials, the ceiling, etc. Bodies block high frequencies pretty well, so a measurement in one spot in the room could be totally different from another. Low frequencies create massive nulls and peaks throughout the room and listeners in the back row by the wall or corner might be getting pummeled with bass that's not present at the mixing or measurement position. 

Stay safe, and if it's a health concern, stay away, if possible. Excessive SPL exposure is a big concern of mine. I wish the industry would get serious about regulation. It's way out of hand and modern soundsystems are so incredibly capable, especially at the huge EDM/rap festivals that are all the rage these days. 

http://www.sciencemag.org/news/2014/09/sounds-you-cant-hear-can-still-hurt-your-ears

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Gasp!  Gag!  Chortle!  Swift and coarse inhale!  MY MIND IS TOTALLY BLOWN BY THAT ARTICLE!  SOAEs?!!  I apologize for the all caps but:

"Then, they used probes to record the natural activity of the ear after the noise ended, taking advantage of a phenomenon dubbed spontaneous otoacoustic emissions (SOAEs) in which the healthy human ear itself emits faint whistling sounds. “Usually they’re too faint to be heard, but with a microphone that’s more sensitive than the human ear, we can detect them,” Drexl says. Researchers know that SOAEs change when a person’s hearing changes and disappear in conjunction with hearing loss."

  How the fuck does THAT work?!!  Sorry for cursing.  But, how the fuck?!  Sorry twice.  That is Stephen King's "The Cell," last train to crazytown, Japanese Hell, twisted biology sci-fi insanity dude!

  Fascinating also about mids and highs vs. bass hearing loss.  Thank you for that awesome information Mr. RScottATL!  Seems like I am totally getting hit with subs, but at least the rest is ok.

So remember how it's far less uncomfortable if the cans are turned up, filling in the mids and highs?  What is up with that?

Thanks for that link Constantin!  They say 25dB of protection, but with that flat-response filter that might really help this bass blast thing...  Might.  Anyone have any stories?

This is by far the most free time I've ever had on a job...  By the way this is not in a small club, it's in the Superdome.  The echoes alone in this giant space are really cool, and some kinda sound like a space battle.  But I bet there are "pockets of bass" all over.

Dan Izen

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my two cents in complicating this interesting question and by no means is this a definitive answer:

part of the problem with earplugs not blocking out enough sound is due to the fact that bones in the skull transmit sound to to the main auditory pathway.

some hearing aids (and bonephone type headphones) work on this principle, using what is called, generally, conductive hearing.

as indicated in responses to this thread, above, in discussion and according to the info in the link below, the resonances and anti-resonances that occur are complex. the article does not provide a definitive answer to the question at the top of this thread. it merely indicates (without breaking this down into extreme granulation) a lot is going on and resonance occurs all over the place.

http://www.tinnitusjournal.com/detalhe_artigo.asp?id=169

my conjecture about bass frequencies is: if you're feeling bass frequencies in your chest there's a lot them absorbed by brain bones and contributing to the neural processing, and not in a good way.

there are no pain receptors in the brain itself. when you have a headache the pain is generated by other receptors, but localized/realized as being in the head.

the principle is similar to the pain in the shoulder or arm when someone is having a heart attack: there are no pain receptors in the heart muscle, so receptors nearby do the job of indicating trouble.

if you're feeling sound pressure, or anything else for that matter, on your head it's on the skull bones and they absorb sound and simultaneously attenuate sound.

if you're feeling bass frequencies in your chest similar vibrations are most likely affecting the guts of your head, but you can't feel it in your head because of the lack of sensation receptors there.

the most direct source of the sound absorption, appears to be the parietal bones above the ears that go up to the temples, generally.

i get a good result at concerts by wearing 3M Peltor X5 hearing protectors with or without earplugs depending on the volume level.

https://www.google.com/search?q=3m+peltor+x-series+over-the-head+earmuffs&ie=utf-8&oe=utf-8#q=3M+Peltor+X5

some people laugh or snicker or stare when i put them on but when the house lights go up at the end of the show i'm pleased with the result. they do shield a very small portion of the parietal area and other skull bones below and around the ear and by design it seems to work that way in addition to protecting the ear canal.

in getting back to conduction, resonance and internal attenuation i would guess that everyone's head bones are different in thickness and a larger head wound mean a person would have more bone mass and generally more biological fluids and that both bones and fluids cause and/or contribute to more or less resonances or attenuation depending on the circumstances, so results will vary.

science has a generally good overview of the situation does not have a definitive answer to the problem of resonances as it is not all worked out yet.

 

 

 

 

 

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10 hours ago, Izen Ears said:

Hey NB, these custom earplugs with a flat-response filter - how does one get these?!  I haven't heard of these, and I bet they'd be a lot better than what I have now!

Just find your local audiologist. Any place that sells hearing aids will be able to do earplugs.

The response isn't perfectly flat but it's close enough that you can mix with them in and your ear will compensate anyway. I put them in 15 mins before and by the time the show starts I have forgotten they are there.

http://elacin.com/hearing-protection/music/

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  Holy moly Mista Gerald that is a sheer ton of awesome and terrifying information!  This the loudest place I've been in since Bon Jovi in 1988 at the Blaisdell Arena (high school).  I feel a weird guilt for the live sound guys here who's ears are assuredly shot to hell, but since they're young they don't care enough.  With the barrage of sound I'm feeling it's surreal to see dudes just walking around without earplugs.  Sad.

  Regarding the brain jelly, I've never understood how someone can get slammed in the head and not harm his brain; it's such a soft spongey substance you'd think at least part would get damaged from being violently jerked.  Thinking of all the sub freqs going right through my body on this gig, it seems likely there would be SOME negative effect, like the vibrations would really "shake up the jelly."  So, darn, there's just no answer yet for the question then huh?  C'mon Science, what're you waiting for?

  Thank you for the Peltor X5 sir!  That thing looks exactly perfect for this gig, wish I had em.  And I hope someone gives me a funny look because I'll hit em back with a "can't help you, sucker!" return funny look.

 Today's the last day, and prolly the worst offender of the lot as well, Puff Daddy.  I brought in a cheaper pair of hearing protection cans and tried em out for the sound check this morning.  They're slightly better than the HNs, but without the "fill-in freqs" it's still pretty uncomfortable.  I feel like they're better because they are tighter around my head?

I did notice a major difference for the better when I pinched the back of my ears, that parabolic-ey part.  The bass was greatly reduced, but it physically hurt after a little while.  I'd rather have some epidermis pain than hearing damage tho.

NBJersey, thank you for the link!  Those seem pretty great albeit pricey.  Less so now I guess.  I should get a pair just to have em.  I never thought of trying to find an audiologist.  Doh!  Double doh!

Love dis group!

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I would very much recommend that anyone who reads this forum on a regular basis (and thus is probably some sort of location sound pro) get your hearing and ears checked by an ENT doc once a year.  Talk to them about what you do and what you've been exposed to, including loud sounds, colds or viruses and shocks to your head (like from a car accident etc).  Go over the hearing test plot with them--you will find it very familiar looking, with frequency plotted against sensitivity.  The news can be shocking (what you've lost) but good to have in mind in making mixing decisions (esp EQ).  It's important to do this annually so you can spot trends--skipping years will make it much harder, if not impossible, to determine the cause of changes in your hearing.  Do protect yourselves, folks.

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I have been meaning to get my hearing tested on a more regular basis, and like so many other things I let it slide.  It's too easy to ignore things that aren't a problem yet, which I think plays a part in why people knowingly do things that harm their hearing.  The repercussions come much later in life.

I am do for new musicians earplugs and new molds for my in ears, hopefully that will get me in the habit of checking my ears.

The musicians earplugs are great for concert work.  They are clear enough that I am able to mix with them in, especially once you get to know them.  When I did live music mixing I always wore them.  Usually put them in when the band's were loading in and didn't take them out until my shift beer at the end of the night.  The volume level is the biggest thing I didn't like about mixing live music.

Now when I'm recording live music I use my molded etymotic in ears inside of double wall construction ear muffs, and it's usually enough that I can hear what I'm doing without blasting my ears.  The bass is still a problem.  So much bass still bleeds through your bones etc that I can't ever tell what my low frequency mix is like.

Some good information in this thread.

 

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  • 2 weeks later...

I'm getting to this thread a little late, but want to add a few thoughts and support much of what's already been said.

It's true that low freqs can seem painfully loud, even with with your ears completely sealed, because low freqs are transmitted through the body, to the hammer, stirrup, and anvil and rattle the cochlea (remember 4th grade anatomy?). The good news is that the low freqs we're likely to encounter that way are much less likely to cause hearing damage, at least of the type we normally experience as sound mixers.

A bit about NRR (Noise Reduction Rating): The NRR is a standard for hearing protection derived by an OSHA formula to give people a general idea of how much they are protecting their hearing, and legal guidelines for employers to protect employees. However, keep in mind that ear plugs or headphones with an NRR of 20dB does not mean that all sound will be reduced by 20dB; the real amount of protection depends on the type of sound being reduced. The factors in the OSHA formula may not accurately represent the noise we are likely to encounter as sound mixers, so using the NRR may give us a false sense of security. Generally, hearing protection attenuates high frequencies much more than low frequencies, but high frequencies are much less likely to have the energy (in dB) of lower frequencies. Also, mid and high frequencies are what we rely on for subtle speech characteristics that add clarity, and, generally, is what is affected by hearing loss.

The Remote Audio HN-7506 are intended, first, to allow accurate monitoring in high noise environments, and, second, to protect ears, not by keeping harmful sound out, but by allowing comfortable, lower monitoring levels. Of course, the extreme physical isolation of these headphones gives significant hearing protection, but the product is not marketed as a stand-alone hearing protection device. Although, when I'm shooting at the gun range, it is clear to me that they are much more protective than what is offered at the range!

ATL shootout high noise sm.jpg

 

 

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