Today’s market is represented by thousands of models of headphones: from cheap Chinese NoName-plugs to exclusive. Prices driven by customer requests and technology. On the technology of best noise cancelling headphones, installed in most closed-type headphones, today we will talk, and most importantly – we will find out the reasons for the headache with long listening to such “ears”.
Active noise cancellation system. History and working principle
The history of development of active noise cancellation system (hereinafter – ASP ) begins in the distant 1934 , when inventor Paul Lug receives a patent describing the principle of suppression of sinusoidal signals emitted by the loudspeaker. In 1950, Lawrence Vogel first implemented a noise suppression system in helicopter cockpits and aircraft parlors.
Prior to the headphones, ASP reached back in 1957 , when Willard Meeker on the presented working model of overhead headphones was able to cut off noise at an audio range of 50 to 500 Hz. The first serial model of headphones with active noise reduction was introduced by Bose in the late 80’s and was used in aviation.
Bose Quiet Comfort: The Beginning
The principle of the ASPnet, in terms of physics, is very simple. Any sound is represented by a wave, so you can create its mirror image – an inverted wave that completely extinguishes the original one.
Inside the headphones, equipped with an active noise reduction system, there are microphones. Their task is to measure the level of ambient noise. The external audio signal is converted into an inverted wave and transmitted to the main speaker. The new wave acts in antiphase (minus the useful signal – music) to noise and, thus, reduces its sound to zero.
It would seem that the use of technology of active noise suppression should significantly improve the life of avid music lovers who do not represent a way to work, walks or active rest without headphones bending headphones, musical drive and rhythm. The number of models equipped with ASP is really growing by leaps and bounds . The market includes headphones of various price categories and form factors: from inexpensive compact gags to weighty studio monitors. The noise cancellation system is being improved every day, the quality of music playback is growing, manufacturers are finding new and new marketing solutions for the popularization of headphones with Noise Cancelling. But there is a category of people who, with all their positive attitude towards portable sound, are forced to abandon all technological advantages of “perfect headphones” for one simple reason – intolerance of the system of active noise suppression .
Wearing headphones with an active noise reduction system and going to the street, you yourself without understanding, deceive the brain. Going to the meeting passers-by, a noisy track, the rumble of the wheels, a sharp wind – the organs of vision clearly draw a picture of what you are on the street. But the organs of hearing testify to complete silence. This discrepancy causes the brain to be confused. Alas, the headache is assured.
Reason two: monotonous stimulus.
There is only one “but”. As a result of such constant noise jamming, monotonic sound waves act on the eardrums. This does not mean that we should hear a rumble or any extraneous noise. The brain perceives only a variety of sonic tones for a particular audio or track, but the nervous system … The action of such vibrations is the principle that is the basis of the active noise cancellation system and it is impossible to predict which organism it will lead to nausea and headaches.
Reason three: silence is not always calm.
Despite the fact that listening to music in headphones with an best noise cancelling headphones system about absolute silence can not be said, the very principle of the ASPnet intersects with the very “absolutely quiet room”. People, whose body is not adapted to this type of headphones, will feel headache and nausea after 1.5 – 2 hours of operation.
The fourth reason: the enemy is my bass
Depending on the height, all sound frequencies with equalization are divided into: high, medium and low. The system of active noise suppression is best handled precisely with the cutoff of low frequencies, which are predominantly saturated with the surrounding noise of the street. Worse things are high, because there is a risk of setting a useful sound signal, represented by music.
Mirror sound wave, reproduced in antiphase with the purpose of suppressing ambient noise, is most saturated with low frequencies . Low frequencies cause maximum vibrations when exposed to liquid, and if you take into account the fact that the human vestibular apparatus is filled with endolymph , then the constant vibrations from the bass bass and cause a headache.
Reason five: structural disadvantage
Another reason why an owner of headphones with active noise reduction system can constantly accompany headaches is too tight a headband. However, this is a common problem with overhead headphones and it’s hardly worth blaming ASP.
How to avoid useless acquisition
Of course, best noise cancellation headphones have several advantages: listening comfort, high level of sound detail and safe volume level. Alas, to foresee how exactly your body will react to ASP. Before you give your blood.