What is the NRR of headphones?
Written by Thepphong Chaiyaratthi on August 17, 2020
Compiled by Ranakrit Sriphumma on August 31, 2020.
NRR is the Noise Reduction Rating (NRR) of a particular noise reduction device.
Which is a value obtained from testing in a laboratory.
However, it is difficult for devices to reduce noise in real-world use.
It is equal to the results of laboratory testing due to several factors.
The study found that the actual noise reduction properties of the device
It is only 1/3 or 1/2 times the value obtained from the laboratory.
There is also the issue of the diversity of wearers.
This is shown by the standard deviation values being 2-3 times higher than in the laboratory.
And how to calculate the noise reduction value of devices like headphones
We can't bring the noise reduction value on the headphones.
Let's subtract the volume of the sound we receive directly.
For example, if we go to practice shooting at a shooting range,
And the volume of gunfire at the shooting range is 110 decibels.
If we use noise-reducing headphones with an NRR of NRR 23
The volume that our ears receive will not be reduced to 110 - 23 = 87 decibels.
But we need to subtract the NRR value by 7 and divide by 2.
Therefore, the loudness that our ears receive after wearing headphones with an NRR of 23 will be
23 - 7 = 16
16/2 = 8
110 - 8 = 102
Therefore, the sound level that our ears may hear when wearing noise-reducing headphones will be 102 decibels.
This is a table of popular gun sound levels.
It can be seen that a pistol equipped with a silencer will have a noise level of 120 decibels or more.
And a pistol without a silencer will have a noise level of 140 decibels or more.
While rifles equipped with silencers will have a noise level of 120 decibels or more.
And a rifle without a silencer will have a noise level of 145 decibels or more.
And when compared to the noise levels in everyday life
The sound of a person whispering is about 30 decibels.
The noise level of a conversation is around 60 decibels.
And the noise of a jet engine is about 140 decibels.
Sounds louder than 90 decibels can cause ear injuries.
If you listen for a long time and the sound is louder than 120 decibels
It can cause immediate ear injury if there is no adequate ear protection.
Even headphones with an NRR in the low 20s will not be able to reduce decibels significantly.
As the numbers suggest, having noise-canceling headphones is still better than not having any at all.
Because noise-reducing headphones act as a medium between the sound source
(Here it's a gun in a shooting range) and our ears, keeping our ears from getting hurt.
From the loudness of the sound directly, it reduces the risk of ear injuries.
Resources
https://www.ammunitiontogo.com/lodge/silencer-guide-with-decibel-level-testing/
Visited on 17/8/2020