After a week of hard work, it finally ushered in a weekend to sleep in, but the children upstairs started to bounce early in the morning, the neighbors who moved in next door were beating, and even the construction site of the new community on the opposite side would be reported from time to time. The noise of “zizizizizizizizizizizizizizißËßËßË”. During countless tortures, you picked up your phone and prepared to buy a noise-reducing earplug, but the question is, which earplug has a good noise reduction effect and does not hurt your ears after wearing it for a long time?
First of all, we need to understand What is the sound intensity?
Take a plane perpendicular to the sound propagation direction, and the energy per unit area per unit time passing through the plane, or the sound power transmitted by the sound wave per unit area, is called the sound intensity. The unit of measurement of sound intensity is expressed in decibels (dB), so the sound intensity is roughly divided into the following categories:
1 decibel just heard the sound
15 decibels feel quiet
30 decibels whispering volume level[ br]The hum of the refrigerator at 40 decibels
The sound of normal conversation at 60 decibels
70 decibels is equivalent to walking in a downtown area
85 decibels on the road where cars are shuttled
95 decibels motorcycle start sound
100 decibel decoration electric drill sound
110 decibel karaoke, loud MP3 sound
120 decibel sound of an airplane taking off
150 decibel sound of fireworks
Generally speaking, The sound intensity suitable for sleep is about 15-35dB, if it exceeds 40dB, it will interfere with sleep. If you accept 50dB noise at night for a long time, it is easy to cause cardiovascular disease; at 55dB, it will have a negative impact on children’s learning; at 60dB, people wake up from sleep; at 70dB, the incidence of myocardial infarction increases by about 30%; more than At 110dB, it may cause permanent hearing loss.
Next we have to understand what is the noise reduction value.
The quality of an earplug is measured by its noise reduction value. The higher the noise reduction value, the better the anti-noise effect. At present, there are two international standards for noise reduction value of sound insulation earplugs, SNR and NRR. SNR is the single value noise reduction value tested according to the international standard ISO 4969-2; NRR is the single value tested according to the American standard ANSI S3.19-1974. Value noise reduction value. In comparison, the SNR of the same earplug is about 3 decibels higher than the NRR.
In short, when the surrounding sound intensity exceeds 40 when sleeping, we should consider wearing noise-reducing earplugs and buying earplugs with high noise-reducing value. Xiaohui recommends the Ning series earplugs under the American century-old brand 3M.