Soundproofing helmets?

[caasland]

Has anyone tried to add soundproofing to their helmets?

Some of these products come to mind:

http://www.greengluecompany.com/

http://www.sonicelectronix.com/item_7942_Accumat-AMT050X2-by-Scosche.html?utm_source=froogle&utm_medium=organic&utm_campaign=froogle&rkg_attid=459442119&zmam=75672847&zmas=1&zmac=1&zmap=7942

[Cablebandit]

[Carbonero]

Much of what we "hear" in our helmets is not only true sound, but it's also vibration transmitted directly through the shell and liner to our heads. You'll never properly "sound proof" your helmet. To do it, you'd need some sort of mid-layer that absorbs and suppresses vibrations; perhaps a liquid/gel mid layer that FULLY isolates the inner (head-touching layer) from the outer (shell/impact layer). For that to happen, you're talking about a full-floating helmet that will be rather pointless in terms of crash protection.

Even with ear plugs, the low-frequency vibrations will damage your hearing over time. Mitigate it with ear plugs, a good aerodynamic helmet, then live life knowing that the perfect hearing of a child is one of the things you're giving up living your life your way.  

[Cablebandit]

The upside of losing your hearing is not having to hear other people's kids.  

Oh, and saying WHAT and HUH a lot.

[X1Glider]

Carbonero, I have been wondering for the past year about a gel type liner instead of EPS.  2 things got me thinking about it.

1. I have a pair of over ear head phones that use a silicone/gel type surround over the ear cups that do a banging job of isolating vibration and therefore resonance of the sound chamber.

2. Dr. Scholl's replacement insoles.  I have these blue gel work insoles that are pretty thick and are pretty firm that are comfortable and dissipate impacts of each step.

It seems to me that a dense enough gel can be produced that would allow the same absorbtion of G forces as EPS liners.  But the thing is, it would not crush, therefore it could rebound back into shape then be able to absorb multiple impacts.  An added plus would be that the gel could do a much better job of disipating energy from the impact in many different directions over a larger surface area instead of the energy effecting a small local area.  By that theory, it might be possible to use a softer gel since more energy could be absorbed instead of transfered to the skull.  (Kind of like the woman jumping up and down on the Tempurpedic mattress and not spilling the wine) Plus the gel would be nice and quiet rather than resonating like a speaker box or acoustic guitar body.

Downside is that gels are heavy compared to styrofoam.

Just a thought.

[caasland]

Foam earplugs aren't the complete answer (at least for me). Get a pair that attenuate enough windnoise, and I can't clearly hear the Sena speakers. Get a pair that I can hear the Sena's through, and the windnoise drowns the Sena's.

Get a pair of custom earphones (Westone) which works well with the earphone Sena clamps, but they block so much noise that I can't hear other vehicles (horns etc) or people talking to me at gas stations. Plus, more fiddling with wires and crap, I'm trying to reduce the fiddling I have to do in order get riding.

Part of the problem is that I ride an FJR. After solving the windshield buffeting issues the noise remains. Can't trade the FJR for anything until I fix the tranny (no second gear) so I'm keeping this a while.

It helped to get a quieter helmet (Bell Rs-1), now if I can just make it a little quieter so that I can use 19-25 db earplugs instead of the 33-35's that would be great ... and the reason for asking about this.

[caasland]

Much of what we "hear" in our helmets is not only true sound, but it's also vibration transmitted directly through the shell and liner to our heads.

That's why I posted those links. The green glue or accumat would be between liner and shell, hopefully dispersing the vibrations, and I'm wondering if anyone has tried it.

Even with ear plugs, the low-frequency vibrations will damage your hearing over time. Mitigate it with ear plugs, a good aerodynamic helmet, then live life knowing that the perfect hearing of a child is one of the things you're giving up living your life your way.  

I've already got mild hearing loss, I came out of my mom this way, so I've never experienced the "perfect hearing". I use hearing aids most of the time which makes me aware of what other's hearing is probably like, and knowing it will likely be worse as I get older I am protective of what I have left. Thus the reason why I am tackling which issue.

[caasland]

The upside of losing your hearing is not having to hear other people's kids.  

Oh, and saying WHAT and HUH a lot.

Not to mention not being able to hear machinery and air conditioning noises and squeeks and rattles.

But there are too many downsides, like mis-hearing a question, only to answer and realize I'm waaaaay off topic as the conversation stops. It's only funny if the people around me know that I have substandard hearing and not wearing my aids.

My favorite exchange:

Friend: "You know they make really small hearing aids?"
Me: "No, I've never slept with a woman with hairy legs."

Laughter ensued.

Another side-effect was realizing just how much brain effort I was using deciphering what I thought I heard and trying to piece it together. As a Norwegian I don't have a lot of brainpower in the first place and it was just easier to withdraw from social situations entirely.

I should have gotten hearing aids looooong before my career depended on it. It was $5k wisely spent.

Bottom line ... quieter helmet = less hearing loss but still able to hear traffic and music and poeple. That's what I'm trying to achieve.

[Bounce]

+1 ear plugs. Then you aren't stuck with a one-helmet mod.

[Carbonero]

Interesting thoughts. I don't know quite enough about physics to yay or nay it, but it seems to me that Just having a single gel insert wouldn't be the optimal way to go. I feel like gel, just being a thick liquid with some air introduced, wouldn't compress enough on its own to absorb much. I'd think two separate layers of gel, or a gel layer separating two layers of EPS might be the way to go. I'd worry about cohesive integrity, twisting, misshaping, etc.

We have any physicists on board who could speak to this...?

Carbonero, I have been wondering for the past year about a gel type liner instead of EPS.  2 things got me thinking about it.

1. I have a pair of over ear head phones that use a silicone/gel type surround over the ear cups that do a banging job of isolating vibration and therefore resonance of the sound chamber.

2. Dr. Scholl's replacement insoles.  I have these blue gel work insoles that are pretty thick and are pretty firm that are comfortable and dissipate impacts of each step.

It seems to me that a dense enough gel can be produced that would allow the same absorbtion of G forces as EPS liners.  But the thing is, it would not crush, therefore it could rebound back into shape then be able to absorb multiple impacts.  An added plus would be that the gel could do a much better job of disipating energy from the impact in many different directions over a larger surface area instead of the energy effecting a small local area.  By that theory, it might be possible to use a softer gel since more energy could be absorbed instead of transfered to the skull.  (Kind of like the woman jumping up and down on the Tempurpedic mattress and not spilling the wine) Plus the gel would be nice and quiet rather than resonating like a speaker box or acoustic guitar body.

Downside is that gels are heavy compared to styrofoam.

Just a thought.

[Dan K]

In the 80's, my high school football helmet had multiple little rectangular gel pockets (like slightly elongated cubes) in rows and columns throughout the inside of the helmet.  Maybe that was better for multiple as opposed to single impacts?  

My guess is the styrofoam base is a better protector from impact, but loses its protective abilities after one shot, as opposed to the less effective gel helmet which keeps on giving, collision after collision.

- Dan

[dietDrThunder]

Those methods won't work. The mat in particular is not effective sound-proofing material. What it does is dampen resonant vibration in body panels. Applying this material to a helmet shell would have very little if any effect. It's also extremely heavy, and could easily add 50%-70% of the weight of your helmet...but at least it would still be loud

[KLRchickie]

While you're riding along, hearing the noise, try blocking various spots between your helmet and your neck with your left hand.  ZED wears an RF1000, which many people call quiet - he finds it damn loud.  Turns out that there is a bit of a "gap" in where the neck padding of the helmet meets with his neck, just behind the jawbone.  If something is tucked in there, the wind noise he hears inside the helmet diminishes significantly.  Some helmets have much cushier neck padding than others.  We've pinned a little piece of polar fleece in the gap on his on some trips and it seems to help somewhat. 

This is in addition to earplugs.