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I have a hearing condition and need to wear ear muffs on my scooter.

My muffs are 3M Peltor with a dB rating of 35dB.

When riding my bike, the combined noise from the engine and the wind is about 80dB.

Now in theory that should get me into about 45dB, but it seems the wind buffering makes it louder.

In other words, the muffs take off 35dB at rest, but with movement and wind they get louder from inside my head because of the wind buffering.

Are there any specifications or any research done on wind impact decibel levels on muffs for ear protection?

AndyT
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Bruno Vincent
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  • I think you'll find that the ability of any ear protection device to attenuate direct wind noise will depend strongly on the shape of the outer shell, the materials in use, and even the shape of your head. Basically if you can get laminar flow across the head-muff combination you'll minimize wind noise in the first place. There's no magic formula. – Carl Witthoft Jan 20 '17 at 13:53

2 Answers2

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The amount of protection offered by ear muffs depends on a number of things.

Firstly, how the muffs are constructed & the materials used and the sound attenuation properties of those materials.

The other thing that is important is how the muffs are worn. You probably know that the cup of each muff must fully encapsulate each ear. For ear muffs to function properly there must be a seal between the cup of each muff & the skin around the side of the head.

Entrapment of hair by the muff cups will reduced the protection offered by the ear muffs because that can create a gap between the skin & the muffs which will allow air and sound to travel through the gap.

While riding your bike it is mostly likely that your head is moving, even though imperceptible vibrations, road roughness, jolts, whatever. Such movement can cause the seal between the muff cups and the skin to be broken, thus letting in more sound into the ear.

Also, if there is a tight fit between the muffs and a helmet any contact between the helmet and the muffs may cause the muffs to move and again breaking the seal between the muffs and the skin.

To improve the noise reduction you receive while riding your bike you may need to also insert ear plugs in addition to using ear muffs.

Fred
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    Another point is that the ear muff protection is usually rated for air->muff->air path, and part of the attenuation happens at the air->muff interface. If the muff plastic touches e.g. helmet plastic parts, it provides a more direct way for sounds to pass. – jpa Jan 20 '17 at 07:18
  • I wear no helmet, not needed for scooter – Bruno Vincent Jan 20 '17 at 10:25
  • And Fred, thank you for the answer, but there is no mention about wind parameter...! – Bruno Vincent Jan 20 '17 at 10:27
  • Combining equally rated plugs and muffs will result in only a 3dB improvement. So if you have a set NRR 33dB earplugs with a pair of NRR 33dB earmuffs, the resulting NRR will be 36dB. – DLS3141 Jan 20 '17 at 21:59
  • Actually the correct number is 5db for plugs / muffs combined, not 3db, and this is not my question! – Bruno Vincent Jan 21 '17 at 01:41
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Why not wear foam earplugs? The right earplug, properly used, have a NRR of 33dB, which is really close to the 35 dB rating of your earmuffs. 3dB is considered the minimum human detectable threashold for sound, so it's unlikely that you'd notice any difference even in ideal conditions.

It's the ideal conditions part that typically causes problems with earmuffs. To work properly, ear protection, plugs or muffs, has to block the path of the sound from reaching your eardrum. They achieve this by creating a sealed barrier between the sound and the eardrum.

While slightly more effective, the muffs have three disadvantages in achieving this seal. First, they're sealing against a much larger and flatter surface area and using a fairly weak spring to do so. This means the seal can be disturbed fairly easily and noise can intrude. Second, there are lots of common things that can get between the seal on the muff and the wearer's skin, typically eyeglass temples and hair are the big offenders here. Third, they're much more likely to become dislodged.

I suspect that in your case, it's some combination of those factors coupled with airflow over your head pushing on and disrupting the seal between the muff and your head.

Earplugs on the other hand achieve a good seal much easier and unless you have really hairy ear canals like Yoda, they also don't have problems with foreign object disrupting the seal. The biggest problem with earplugs is in teaching people how to wear them correctly, but it's easy to do. The other big plus is that earplugs are much more discreet than those big yellow Peltor muffs.

DLS3141
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  • Thank you for great answer, however , it still doesn't address the question about wind buffering decibel increase parameter...! – Bruno Vincent Jan 21 '17 at 01:42
  • @BrunoVincent yes you're right. I have found some studies, but they were all focused on hearing protection for motorcycle riders where the rider wore a helmet. My recommendation for earplugs over earmuffs still stands – DLS3141 Jan 21 '17 at 01:51
  • Hmm so no research on that? I find it puzzling...how do you protect outdoor workers? What about rain, storms, vibrations, what about impact on muffs(tool hits it or bump machinery)...maybe I'll email muff companies – Bruno Vincent Jan 21 '17 at 07:24