Front view of used Shoei Neotec large size helmet showing no signs that it has Quiet Ride noise reduction earmuffs installed in the helmet. Reduces engine sounds from stock exhaust motorcycle and wind noise by over 50% at ears.
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Thin noise reduction earmuffs shown in helmet will reduce wind and engine noise at ears by over 50%. |
Loop Velcro is stuck on back side of earmuffs that will Velcro to air bladders with hook Velcro stuck on air bladders. |
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First step, remove side padding shown in picture above. Grind off chin strap metal connection to helmet and cut off secondary connection. They are in the way for installing air bladder under earmuff in earmuff pocket. |
Using a high speed grinder with a 1/4" carbide burr die grinder bit works very well to grinding off factory installed metal chin strap. Grind off ends of pop rivet holding metal chin strap connection to the helmet. |
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Metal chin strap connection to helmet on each side of helmet must be relocated 2" lower and forward as shown so metal chin strap connection and chin strap will not be under earmuff. I used some 1" wide red nylon strap to replace original Shoei 1" black nylon strap that came with the helmet because I accidently cut black strap too short when shortening black original strap. Method of shortening chin straps: Chin strap must be shortened 2" on each side by shortening chin strap connection to metal connector to the helmet. |
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| To attach 1" wide strap securely to metal strap attachemnt to helmet I held the strap in a vice and melted 1/8" holes thru strap using a torch to heat up a small nail. I found some very small 1/8" by 3/8" in length metal pop rivets to secure shortened strap to metal connector. |
The picture above shows melted 1/8" hole thru nylon shortened chin strap for reinstallation of metal chin strap connection piece to be installed in new 3/16th inch hole drilled in the helmet for attaching metal chin strap connector. |
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Pop Rivet Gun |
2 pictures of shortened chin straps by 2" to compensate for relocation of metal chin strap connections 2 inches lower and forward on each side of helmet. Reattach metal chin strap connectors using short 3/16" pop rivet. |
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An earmuff pocket must be cut out of Styrofoam insert on left and right side of helmet to accept earmuff. |
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The picture above shows a slot cut in side padding for air to flow from air pump to air bladder. |
Shown above a thin piece of plastic was placed over slider mechanism for sun shield to protect mechanism and loop Velcro that comes in kit is stuck in proper location to inside earmuff pocket.
Shown in right picture are the plumbing parts to install in a helmet design to apply air pressure to earmuffs, forcing earmuffs to seal around ears. -----> |
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The picture above shows airline from each air bladder going under Styrofoam side padding and under side foam padding when that are installed on each side of helmet and connect to air pump at back of helmet. |
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Shown is location of airlines from air bladders to air valve and air bladder pump. |
This picture shows two small cable clamps that hold air valve pump with airlines attached securely in place on back of helmet. The cable clamps are stuck to the helmet with 3M VHB 5 lb. outdoor tape. |
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Styrofoam side padding is reinstalled in helmet and all cable clamps are holding air valve and air pump bladder securely to the helmet. |
Squeezing the air pump bladder repeatedly will force air into bladders between back side of earmuffs and inside of helmet shell forcing the earmuffs to seal around ears. To release air pressure in air bladders push down on the pressure release valve. |
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Testing noise reduction at various speeds was performed by riding a 250 Yamaha Virago shown below at various speeds using sound level meter with remote control installed in the Quiet Ride passive noise reduction earmuff installed in a Modular helmet. |
This is a picture of a quality sound level meter with remote lapel mic that is installed in helmets to measure sound levels at ears. |
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The small lapel mic is installed in earmuff to measure sound levels in earmuff from 35mph and 65 mph. |
| General test results for all stock full face or modular helmets before installing earmuffs and after installing noise reduction earmuffs.. |
CRUISING SPEED
35 mph
45 mph
55 mph
60 mph
65 mph
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1. Sound level in stock helmets with remote mic from sound level meter placed across from ear in the helmet.
91 dB
94 dB
98 dB
99 dB
100 dB
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2. Sound level in earmuff with remote mic installed in noise reduction earmuff in stock Helmets.
80 dB
82dB
84 dB
86 dB
88 dB
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| Test results show an average noise reduction for wind and stock engine noise of 12 decibles (dB). For every 10 dB of noise reduction you ears perceive a sound level reduction of 50%, hence the noise reduction is just over 50%. |
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World Health Organization
Noise Dose Chart: Noise Exposure Limits
The risk to your hearing from noise exposure depends on how loud it is and how long you're exposed to it. This noise dose chart shows the acceptable safety limits.
Noise Dose Formula
The generally accepted standard to minimize hearing risk is based on an exposure to 85 dB for a maximum limit of eight hours per day, followed by at least ten hours of recovery time at 70 dB or lower (at which the risk of harm to healthy ears is negligible). Then a "3 dB exchange rate" formula is applied, which means that for every 3 dB above 85 dB, the maximum exposure time is cut in half.
Maximum Recommended Noise Dose
Exposure Levels
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| Noise Level (dBA) |
Maximum Exposure Time per 24 Hours |
| 85 | 8 hours |
| 91 | 2 hours |
| 94 | 1 hours |
| 97 | 30 minutes |
| 100 | 15 minutes |
| 103 | 7.5 minutes |
Conclusion
After reading the noise exposure limits above provided by the World Health Organization riders should concluide they have three options to protect their hearing when riding for extended periods of time.
1. Wear quality earplugs to protect hearing.
or
2. Wear a helmet with noise reduction earmuffs installed in their helmet.
or
3. Wear earplugs and noise reduction earmuffs installed in their helmet.
I have tested many full size helmets and modular helmets for sound levels at various speeds. Using the sound level meter shown above shows sound levels at various speeds for all manufacture helmet models without ear noise reduction earmuffs installed to produce very similar sound levels no matter the manufacturer.
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