Active noise reduction practical use. How active noise canceling headphones work

Today, almost half of the assortment in the audio department of any store is equipped with an active noise reduction system. Some say that this is the best invention since the advent of headsets, while others are sure that this is just another ploy to pump out money.

Let's figure out together whether you need to pay attention to such a feature when choosing headphones.

What is it and how does it work

Active Noise Cancellation is a way to eliminate unwanted noise by overlaying specially generated sound.

Active noise reduction works as follows. The system captures the noise to be suppressed through an external microphone and emits a sound wave with the same amplitude but a mirror image of the original sound's phase. The noise wave and the generated sound mix and cancel each other out.

This method of dealing with noise when listening to music allows you to abandon complete sound insulation or excessively increase the volume. These two methods were previously actively used to suppress unnecessary sounds.

The first patents in this area began to appear back in the 30s of the twentieth century, but it came to real application only half a century later. Active noise cancellation technology was originally used in the aviation and defense industries. Only a few years ago it entered the consumer market.

Is it effective

Many people mistakenly consider the active noise reduction system a marketing ploy. Yes, the system will not protect you from all noise, but it performs its direct function properly.

It is generally accepted that a person is able to perceive sounds in the range from 20 Hz to 20 kHz. Most modern noise cancelers cope well with noise from 100 Hz to 1 KHz. This is quite enough to save the listener from conversations of other people, traffic noise and wind.

We perceive vibrations in the range below 100 Hz not only with the ear, but also with the body; here, no noise reduction in headphones will help. As for the upper range, the system is capable of turning high-frequency squeaks or whistles into a calm hiss.

With good noise-canceling headphones, you can feel like you are in a quiet room, even if you are on a noisy street.

Useful features of active noise cancellation

Manufacturers thought, since the headphones are equipped with an external microphone, why not provide the ability to use it for its intended purpose.

Some models allow you to temporarily disable noise reduction and broadcast sound “outside” to your headphones. This way you can communicate with your interlocutor, move safely, or simply perceive information from the outside world without removing your headphones.

Another advantage of models with active noise reduction is the presence of a built-in amplifier. It is with its help that “anti-noise” is generated for the operation of the system, but in addition to this, the amplifier is capable of producing higher quality sound.

Is everything really that smooth?

The active noise reduction system also has its drawbacks. The main one is that these headphones are not suitable for everyone. Don’t worry, the percentage of those for whom the technology is contraindicated is quite low. About 3% of users, when using active noise reduction for a long time, begin to complain of headaches.

Their cause is active noise suppression system intolerance syndrome. It is similar to seasickness, when our brain thinks that the body is at rest, but the vestibular system sends opposite signals.

Likewise, when suppressing noise, it seems to the brain that we are in a quiet place, and the senses send signals that are unusual for this.

Another negative factor is increased pressure on the eardrums, because in addition to music and noise, “anti-noise” enters our ears. This can cause disruptions in the nervous system and lead to headaches.

What are the alternatives?

At the moment, active noise reduction is the most technologically advanced solution. This feature cuts out up to 95% of extraneous sounds when listening to music. In this case, a whole chain of additional elements is used and this affects the cost of headphones and headsets with active noise suppression.

As a counterbalance to this technology, you can use passive noise reduction. It is achieved by sealing the human ear from external noise through massive ear pads in over-ear headphone models or flexible ear pads that can take any shape in vacuum models.

All other things being equal, such headphones are cheaper and simpler in design, which means they are more reliable in operation.

What to choose in the end

First, you need to go to the nearest electronics store with exhibition samples and visually verify the operation of the active noise reduction system. A simple comparison of headphones with and without such a system will immediately give results.

To avoid falling into the so-called “risk zone,” it is better to ask a friend or acquaintance to test the model.

This is how yet another technology, previously in service with the military, is deeply penetrating our lives.

Here you are, do you like silence? - And I love. It’s not even the silence itself, but the absence of external stimuli. While studying or working, you need to focus on the problem/task at hand, and it’s quite difficult to do this when your household is dancing around you or the phone is ringing all over the office... Of course, there are moments when you seeth with particular passion over your work, when you are already drawn into process and nothing can distract you. But what to do when there is no particular desire to do the work, and it’s also impossible to concentrate? For myself, I found a solution in headphones with an active noise reduction system.

Let's start with the fact that I first learned about headphones with an active noise reduction system after reading here
, where hackers actively shared photos and discussed their jobs. The author of that thread mentioned the rather expensive Bose QC-15 headphones (~$500 in the CIS), so an operation was launched to find cheaper alternatives. As a result, the choice fell on Audio-Technica ANC7b - headphones from a well-known Japanese manufacturer that has proven itself all over the world.

▐ Specifications

It would be logical to continue the article with a description of the packaging and delivery set of the device under review, but due to frequent moves over the past six months, all the equipment was lost and only the headphones themselves and the box were left on hand. Initially, in the latter you could find: a hard case for transportation (I have no idea where I lost it), a removable cable (similar), an AAA battery, an adapter for using headphones on airplanes + an adapter for a 6.3 mm connector and a couple of replaceable cables (with a microphone and without).

How much did the complete case cost... Oh well, let’s not talk about sad things, for the last few months I’ve been using headphones with a cable from Philips, which was brazenly pressed out and politely lent to me by a user. On this occasion, I say hello and promise to return the cable. ;)

▐ Design, construction, comfort of wearing

When I first met them, the Audio-Technica ANC7b headphones did not make any lasting impressions on me. Ascetic design due to the use of exclusively plastic in the body materials, classic shape with an arc mount, slight creaking when bending the headphones and turning the earcups. The latter have two degrees of freedom: rotation 90 degrees along the vertical axis and 45 degrees along the horizontal axis.

The headband size adjustment mechanism has 15 positions in 3 mm increments. There are no symbols, so it is assumed that the user must set the desired size once or each time be guided by the clicks that the guides make when changing the size.

The earcups are average (relative to other over-ear monitors) sizes. Traditionally, the manufacturer’s logo, headphone model and “left-right” marking are located on the outside.

The microphones at the bottom of the earcups are part of the active noise cancellation system. The battery compartment is also located here, which is hidden behind the false panel. Any AAA batteries with voltage up to 1.5 V will be suitable.

On the left “ear,” in addition to the already mentioned elements, there is a switch for the ACP system. The activation of the latter is signaled by a bright blue eye-catching LED. There is also a connector for connecting a 3.5 mm audio cable, but it is worth noting that a plug with a larger diameter may not “fit” into this port.

By the way, on the axis connecting the right cup with the headband there is a small raised point, thanks to which you can blindly determine where the right and where the left “ear” is.

The ear pads are medium in size, moderately elastic, and the headband is covered with leatherette. The headphones fit tightly around your head, but do not cause any discomfort.

As for my personal impressions of convenience, I am writing these lines after 5 (or maybe more) hours of wearing the headphones. It's winter outside, in the room it's around 20 degrees - the ears are comfortable. In the summer, of course, there is a slight discomfort, since the ears sweat, but on the other hand, show me headphones that will keep your ears dry in thirty-degree heat?

▐ Sound, compatibility, some aspects of operation

To begin with, do not be afraid of a resistance of 300 ohms. Firstly, this is an indicator when the ACP system is turned off. Unfortunately, the manufacturer did not provide the value of this parameter with noise reduction enabled, but judging by the change in the volume level, the headphones have a very “peppy” amplifier built into them.

Secondly, given the sensitivity of 109 dB/mW, the headphones can be used in conjunction with a smartphone or player, even with the proprietary technology turned off. But here it is worth considering that there will be no volume reserve. So, even for normal listening to music you have to turn the volume up to maximum. In general, for comfortable listening to music in these headphones without noise reduction, you should get a more serious source, for example -.

frequency response

As for the sound quality itself, which is actually a purely subjective concept and ideally I would listen to IRL headphones before buying, I’m a little more than satisfied with the sound. I use headphones mainly at home, paired with an external DAC, so in both modes I do not feel a lack of volume. Moreover, I use it quite often - at least 3-5 hours a day and often with noise reduction turned on (+ sounds of nature or light music). This set makes it possible to completely ignore the roar of the old refrigerator, the conversations of roommates and their movements around the room. At the same time, louder conversations leak out, which is a plus for me personally.

If it were not for such huge sizes (on my already small head, such headphones look very deplorable), I would gladly ride with these headphones in the subway. The bottom line is that ANC works best with lower frequencies, i.e. The subway hum is cut off completely, and the female voice announcing the station remains audible (provided you are listening to an audiobook/podcast or music at low volume). One of the main drawbacks was also noticed here: due to the use of active electronics, the device tends to pick up interference from mobile phones, albeit periodically, but this effect causes some discomfort.

▐ Active noise reduction system design

What exactly is a noise reduction system? First you need to understand that noise suppression there is how active, so passive. The latter is mainly the prerogative of closed monitor headphones. The housings of the cups of such devices do not contain any holes on the outside, and the walls of such headphones are usually quite massive and the material from which they are made often has the ability to dampen sound vibrations. Headphones with the best passive noise reduction have 35-37 dB.

Active noise cancellation, in turn, requires the introduction of electronics into the headphones. The operating principle of this system is quite easy to understand, even if you skipped physics classes at school. Sound is a physical phenomenon that is the propagation of elastic waves in a certain medium. More precisely, sound is a wave. Music, the sound of a jackhammer, the screams of a baby - these are all sound waves that we encounter everywhere. One of the main phenomena inherent in waves is interference.

Wave interference is a mutual increase or decrease in the resulting amplitude of two or more coherent waves when they are superimposed on each other.(c) Wikipedia

But how does active noise cancellation depend on the interference phenomenon? - And such that this method of noise reduction is based on interference! If the waves arrive at a point in the medium (meet) in antiphase, then the displacement of the particles will be in different directions, which leads to a decrease in the amplitude of the oscillations, i.e. sound vibrations coming from outside are damped. Due to restrictions (possibly temporary, because progress does not stand still) imposed by the internal “noise reduction” electronics, it is, unfortunately, not possible to completely compensate for external noise.

This is exactly how the ACP system works. Special microphones located in the earcups pick up external sounds, and the built-in electronics invert them and add them to the music being played, thereby removing external noise.

▐ Internals, autonomy

Lately, it has become fashionable to rate devices for their repairability. In order to keep up with trends, let’s dissect the headphones, and at the same time see what kind of magic is hidden in their casing. Peel off the ear pads:

Under a thin foam filter (not pictured) there is a microphone of the ACP system and a dynamic emitter. To obtain surround sound, the earcups are filled with foam rubber.

Once again we are convinced that the headphone body is entirely made of plastic. On the left cup there are three screws for a CR-VT8 screwdriver - they hold the false panel under which the electronics of the active noise reduction system are hidden.

Further, more: an oval-shaped printed circuit board (click on the picture below for full size) occupies almost the entire internal space of the left cup. Dirt in the area of the audio jack slightly spoils the impression, but overall everything is good.

On the reverse side are two single electrolytic capacitors and a standard 3.5 mm TRS connector.

In the production of these headphones, serial components were used, for example, the eight-legged chip on the right side of the board is the MAX660, a voltage inverter that can act as both a negative voltage source and a boost converter for an amplifier. In the upper left corner - ST V324 (14 pins) - four-channel amplifier with THD (non-linear distortion) no more than 0.01%. Unfortunately, the purpose of the MS located above could not be established. And yes, I later replaced the blue LED with a warm lamp yellow one.

A few words about autonomy. To operate the ACP system, I use a Ni-MH AAA battery. As you already know, I spend ~2-3 hours a day wearing headphones, so I have to charge the 700 mAh battery once every two weeks. I didn’t like the absence of any charge indicator - you can only find out about a completely dead battery through periodic snoring in your ears, accompanied by a slow attenuation of the LED. I also advise you to make sure that noise reduction is turned off, because no auto-shutdown function was found.

▐ Price, results

Audio-Technica ANC7b are excellent closed-back headphones with an active noise reduction system. It copes with its main task of cutting off external noise relatively well. Despite the modest design and cheap case materials, the headphones are well assembled, have a comfortable fit and decent sound. The main flaws stand out: the lack of a charge indicator, periodic interference from cell phones... The price, both on the global and CIS markets, fluctuates around 5-7 thousand rubles (140 - 190 dollars).

Advantages and disadvantages

Active Noise Cancellation System
Autonomy
Sound
Lack of charge/discharge indicator
Interference from mobile phones

In the vast majority of cases, the average music lover has enough of ordinary and high-quality or, as an option, overhead models in order to escape from the outside world and enjoy the inner one along with some marvelous composition.

But there are cases when only noise-canceling headphones will help, and they will not just help, but will improve your well-being and make life much easier. You don’t have to look far for examples - have you tried relaxing in a reserved seat with a fun company next door? Or sleep during a long flight for 8-10 hours? In a rumbling bus or minibus, rest also becomes a problem. Therefore, noise-cancelling headphones are, as often happens, the only option to calm your nerves and calmly escape from the hustle and bustle of the world around you. As soon as you put one of the models described below on your head, the long-awaited happiness of silence and peace comes in the company of your favorite music or radio station.

So, let's try to figure it out. Noise-canceling headphones: what are they, which models deserve attention, what is good for the office and what for the home? Let us designate the most successful models in the form of a rating, taking into account the opinions of experts in this field and reviews of ordinary owners.

Bose QC 25
Bose QC 20i
Sennheiser MM 550-X Travel
Denon AH-NCW500
Jabra Evolve 80 UC

Bose QC 25

It’s not for nothing that this model is nicknamed “The Big Noise Killers.” The manufacturer positions it as an innovative device with the maximum level of noise reduction. Judging by the specifications, the model is capable of cutting out 95% of external noise.

The Bose QC 25 Noise Canceling Headphones are considered an active system and run on a single AAA battery. It lasts for about 30-odd hours. It is also worth noting that the model has excellent ergonomics and fits perfectly on the head. The cups wrap around the ears intelligently, due to which the pressure is practically not felt.

The owners in their reviews appreciated the deep and enveloping bass, as well as the presence of a beautiful and compact case. Also, buyers were quite satisfied with the passive noise reduction system if the battery ran out. Some are put off by the price of the gadget, but, judging by expert reviews, the balance of price and quality is maintained at the proper level.

In addition to the case, the package includes a built-in and convenient remote control, as well as a detachable cable that is compatible with all Apple devices and some gadgets on the Android platform. Many owners have labeled the QC 25 as noise-cancelling headphones for the subway.

Estimated price - 23,000 rubles.

Bose QC 20i

If the previous respondent can be called the best among over-ear and full-size models, then the QC 20i is among in-ear models. And here the nickname “Little Noise Killers” is appropriate. Just like the 25th model, the QC 20i noise-canceling headphones can operate in active and passive mode. To maintain the active mode, there is a built-in battery that lasts for approximately 15 hours.

Some owners in their reviews complain about the not very convenient case where the battery is stored, calling it an “eyesore,” but after several days of use the feeling of discomfort disappears. Users liked the ergonomics of the gadget - the headphones do not fall out and sit comfortably.

Opinions of experts and owners

In terms of sound, the device pleased me: powerful and clear bass, bright high frequencies and well-balanced mids. The only thing that owners note as a minus in their reviews is the lack of “honest” sound, because many musical compositions turn out to be slightly embellished in the output. This is especially noticeable in the high and low frequency ranges. In this regard, it remains to recommend a test drive of the gadget before purchasing, so as not to be disappointed after the purchase. In addition, the high price does not make the purchase frivolous.

The device synchronizes perfectly with all Apple products and some devices on the Android platform. The overwhelming majority of gadget owners position the model as noise-canceling headphones for the office: small, comfortable and practical.

Sennheiser MM 550-X Travel

This model can be called a high-quality station wagon in retro style. The Sennheiser 550 series noise-canceling headphones look like something from the 80s, but, unlike older models, they work perfectly.

In terms of its acoustic characteristics, this model is ahead of the QC 25 in some respects: “correct” sound, balanced bass and “meatiness”. The only thing where the MM 550 series loses is in noise reduction: 90% to 95% for the QC 25.

Owner reviews

Among the undeniable advantages, owners in their reviews note the absence of wires and long battery life in active mode. Also, among other positive features, there are other distinctive nuances that these noise-cancelling headphones have. The review showed that the gadget fully supports SRS WOW HD technology, which means that the owner of the device will enjoy excellent spatial sound.

Among other things, the model fits perfectly on the head and allows you to spend a lot of time doing your favorite activity without any discomfort. Well, the last point that can become critical when choosing headphones is a replaceable battery - a very rare quality even among expensive analogues.

Estimated price - 30,000 rubles.

Denon AH-NCW500

This is a relatively compact model of noise-canceling headphones, which differs from the mass of others in its rather interesting control system. The gadget is equipped with a durable plastic case, which perfectly matches the leather inserts.

The control system needs to be mentioned separately. The universal button for switching tracks, start and pause is located on both parts of the headphones. In addition, on one of the ear pads there is a very convenient volume control in the form of a ring.

As for the active noise reduction mode, it is noticeably weak here when compared with the previous participants in the rating. However, while working or relaxing, you will not hear the photocopier running or the noise from the air conditioner. The active noise reduction mode will drain the battery in about 10 hours in wireless mode, and after that you can connect the wires and work with the passive system.

Users' opinions

The owners speak very warmly about the model in their reviews. Almost everyone was satisfied with the noise-canceling characteristics coupled with excellent sound. The gadget is especially good at bass and high frequencies, which accurately and “truthfully” convey all the information to the listener. Some complain about slight dips in the midrange, but this is noticeable in a number of rare compositions.

Approximate price - 15,000 rubles.

Jabra Evolve 80 UC

The brand is still famous for its Bluetooth headsets, which have completely conquered the business segment. In the new Evolve line, the company focused on the same area, that is, it developed another high-quality gadget for business.

This model is the only one of all those reviewed that can be called a headset. Other competitors have a microphone, but it is built into the earpiece and located relatively far from the mouth, while the Evolve models are equipped with a specially articulated boom for greater convenience. And if in the first case we have mediocre transmission quality due to the distant location, then in the second - everything is exactly the opposite.

By and large, we can say that the Jabra Evolve 80 UC is not only a full-fledged headset, that is, “two in one”. Owners have repeatedly noted this pleasant feature in their reviews, and dispatchers and streamers spoke especially warmly about it. Also, many owners were pleased with the Do Not Disturb mode. If it is activated, the ear pads light up red, thereby notifying others that the user is busy. The battery life of the gadget is quite acceptable and varies within a day. There are also no questions about the sound - everything is almost perfect, and there were no critical comments.

Estimated price - 20,000 rubles.

The most important component of a car's operation is the process of igniting the mixture of fuel and air in the cylinders of the internal combustion engine. Internal combustion engines appeared quite a long time ago, and all this time engineers worked on a system for suppressing low-frequency noise that occurs during machine operation. Energy-saving technologies have led to cleaner, more fuel-efficient vehicles, but cabin noise still remains a problem. Fewer cylinders with more efficient and cleaner engines reduce frequency and increase the likelihood of a more intense and irritating ride for passengers.

Active-noise-control (ANC) technology uses the vehicle's audio system to reduce unwanted noise generated by the engine. To reduce this noise, engineers use active acoustic control, or ANC, to generate noise-canceling signals that are played on speakers in the vehicle's cabin.

A Closer Look at the Active Noise Cancellation System

Active audio sound management is a signal processing methodology that reduces the effective amplitude of audio to improve the signal-to-noise ratio (SNR), thereby partially canceling out unwanted noise. Active noise control technology is also called audio noise reduction (ANR). This methodology is based on coherent acoustics, which accurately reproduces the original sound field in all its forms. It uses amplifiers and microphones inside the car, as well as digital signal processing (DSP) to suppress noise. Sound can be described as a pressure wave consisting of amplitude and phase.

The noise reduction system is built into an audio device that emits a wave with the same amplitude, but with a phase 180° (inverted phase, also known as antiphase) shifted from the original wave. The process of recombination of two waves is based on a physical principle called destructive interference. ANC is achieved using mixed signal or DSP circuits with a control algorithm to analyze the audio waveform to generate an amplified anti-phase wave for the transducer.

These systems increasingly rely on integrated systems (SoCs) equipped with high-performance commodity processors and software infrastructure. Real-time resources are needed to quickly implement and complete feedback control loops for the ANC solution to perform as expected.

The ideal method for implementing such a solution uses digital signal processing (picture above). A typical ANC-based car system uses four or five sound system subwoofers and adds three to six microphones. With this setting, the system can reduce noise in the range from 30 to 250 Hz (the spectrum covers the ignition frequencies of a four-cylinder engine) in the passenger compartment.

Development Features

ANC generates an antiphase (180°) that is ideally suited to this interference source. To get the most effective results, the ANC system must also be located fairly close to the source of the noise, which is primarily transmitted in one direction.

ANC systems use one of two main methods:

Adaptive Removal Method: It relies on one or more microphones to detect noise and generate an anti-noise wave.
Synthesis method: It involves sampling and storing a number of noise cycles and generating a denoising signal based on the stored information.

Such a system is especially useful for applications such as industrial equipment, dynamic systems and home appliances.

In this diagram, the Dff block represents a delay element for the arrival of an audio signal to the speaker. The microphone receives the sound signal and sends it to the G(ω) filter, after which the sounds are mixed to compensate.

The system is typically either predictive, where a coherent audio input signal is detected before propagating further, or feedback control is used, where an active noise controller attempts to overcome interference without an audio input signal. Option 1 is shown in the block diagram above, the second - in the block diagram below.

In a typical configuration, the Harvard Digital Signal Processing Architecture is the core of the system—it can perform mathematical processing and manipulation of real-world signals such as voice, audio, and video. In a noise reduction application, digital signal processing examines the waveform characteristics of the input noise and then generates its anti-noise waveform. Therefore, the human ear receives less “white” noise since the “filtering” occurs in real or near real time.

Codecs are essential in audio applications because it can convert real world analog signals (such as audio) into digital signals for processing by a microprocessor and back to analog for the human ear. Typically, least mean squares (LMS) or finite impulse response (FIR) filters are used, which can change the coefficients during operation, effectively solving the problem of actually estimating noise, and thus maximizing system performance under real-world conditions.

Passive control

Noise control methods are mainly passive and active in terms of control. Passive technique identifies a frequency band of noise and increases the gain of the signal (voice or music) so that it maximizes the signal to noise ratio of that band and in turn produces clearer signal intelligibility. Passive technology is not very difficult to implement, although a series of frequency domain measurements may be required. A method of noise control that is considered passive is called a “noise gate.”

conclusions

Managing sound noise in a vehicle is a complex task because sound is produced by many mechanical components, as well as by the interaction of objects with the road and air. Industrial efforts have done much to reduce vehicle noise. At the same time, concerns have been raised about the complete silence of vehicles - they could pose a danger to pedestrians who may not be able to hear an approaching car.

Active noise control technology is quite effective and can reduce noise by about 20 dB.

Today, the market offers a variety of headphone models, among which you can choose from cheap Chinese models to expensive products. Moreover, their cost largely depends on the technical component. Most closed-back headphones Active noise reduction technology is used. Rumor has it that it causes headaches when listening to music for a long time.

A little history

It is worth considering the history and principle of operation of the active noise reduction system. Music allows a person to relax, cope with strong emotions, it accompanies a person throughout his life. Manufacturers began to think about portable music in the middle of the last century, so in 79 Sony created a cassette player. Within a few years, this device was recognized as the company's greatest invention. In 84, the first CD player was created, and already in 98, MP3 players became available to users, which are still used today. The development of this industry cannot be characterized without mentioning headphones, because they provided good and high-quality sound.

The active noise reduction system began its history in the forties of the last century.. It was then that inventor Paul Luge patented a study that described the principle of operation of sine waves. In '50, Lawrence Vogel used a noise suppression system in a helicopter and airplane. This system began to be used in headphones in 1957, when Willard Meeker was able to cut off noise from 50 to 500 Hz. Already in the 80s, headphones for aviation began to be produced, they used this technology.

How does the noise reduction system work?

If we consider the operating principle of ASP, experts describe it quite simply. Each individual sound is a wave, which means it can be reflected. And this inverted wave will completely cancel out the original one. If we take the example of headphones that use the system, microphones will be located inside. They are designed to measure the level of noise generated. Therefore, the received sound signal is converted into an inverted wave, after which it is transmitted to the main speaker. Here, antiphase to noise functions, while the music is not damaged as a useful signal, due to this the noise is removed.

Effectiveness of the active noise cancellation system

First of all, it should be said that such a system does not work well over the entire frequency range, but in the interval from approximately 100 to 1 KHz. In this area, good headphone models can provide noise reduction down to -30 dB. In the lowest sound range, up to 100 Hz, a person perceives sound vibrations not so much with the ears as with the body, and headphones, no matter what level of compensation they provide, will not save you from noise.

Above 1 kHz the system may even add a little noise. However, this is not a street hum, but a uniform, calm “hissing”, and also very quiet -
it can only be heard in a very calm environment.

In the range of 100-1000 Hz, subject to high-quality implementation, “noise reduction” is quite capable of significantly reducing the sound pressure of the environment. With good noise-canceling headphones, it’s quite possible to feel like you’re in a quiet, deserted room while on a noisy street.

In some models, the noise reduction works truly amazingly. This, for example, is the new Bose line and older Sony models, especially the MDR-1000x: you put on headphones and at first you refuse to believe your ears.

Models such as Sennheiser Momentum 2.0 Wireless, Parrot Zik, and all kinds of Beats do a very good job of cutting out noise. At the same time, in many budget “no-name” options, “noise reduction” can be present only nominally, and the effect of its work tends to zero.

Why does my head hurt?

Many people believe that using such a system makes the music better and the listening experience more comfortable. But it is not so. People are actively using such devices as headphones with active noise reduction systems are becoming more and more popular. At the same time, the market offers products from different price categories, including the usual plugs and full-size models. You need to understand that technology does not stand still, the system is being improved, and the sound quality of music is constantly improving. Manufacturers are also trying to promote devices with this technology by making various marketing decisions. But some buyers are forced to refuse such a purchase, despite the sound quality. This is due to the fact that they do not tolerate active noise cancellation. For some people, the body reacts to the absence of extraneous sounds and the crystal clear sound of music with a headache. The headphones seem perfect, but this effect can occur for several reasons.

The effect of rocking on a ship. If you are familiar with seasickness, if you have a hard time being on ships, then you may find yourself in the category of people who cannot tolerate ASN (active noise cancellation system). You may only represent 7 percent of all users, but chances are you're one of those people. The idea is that when you use these headphones, you are deceiving your brain, just like when you are on a ship. You walk down the street and see passers-by, noisy traffic, a sharp wind. The organs of vision transmit information to the brain that you are outside, but the organs of hearing do not transmit noise due to the use of the system. This is why the brain is confused, which is why malaise and headaches appear.
Monotonous stimulus. Having understood the principle of operation of the system, it is worth emphasizing that for every action there is a reaction. As a result of the system's operation, manufacturers are able to eliminate noise and allow the listener to be completely immersed in the music. But one must take into account the fact that in this case the organs of sound will be affected by monotonous sound waves. And the human brain is tuned exclusively to receive a variety of sounds. It is worth mentioning the peculiarities of the nervous system, which can react negatively to such pure sound. Due to the characteristics of the body, nausea and headaches may occur when using the system. However, it is impossible to predict who is predisposed to such consequences and who is not.
Silence is not the key to peace. Well-known manufacturers test the devices they create in special organizations. Research is carried out in special rooms, so-called absolutely quiet rooms. Almost all extraneous sounds are blocked in the rooms. This creates ideal conditions for testing equipment. But experts are of the opinion that absolute silence does not contribute to a calm state of the body.
If a person finds himself in such a room, he will be haunted by a feeling of anxiety. Within a few minutes he will begin to hear the squeak of a mosquito and the rumbling of his own stomach. Just five minutes of being in such conditions is enough for the body to go into a state of anxiety and restlessness. Studies have shown that a person cannot spend more than 45 minutes in such a room. While using the systems does not create absolute silence because music is playing, the principle of operation of the system affects the concept of absolute silence. After all, when using such headphones, a person hears only music. This is why people may experience headaches and nausea when using devices.
Negative bass effects. When creating music, all frequencies are divided into high, medium, low. The system used in headphones is designed to exclude all low frequencies, which constitute street noise. There is a risk in the system of “suppressing” the useful sound signal, that is, music. A sound wave that is created in antiphase is rich in low frequencies. As is known, they can affect the liquid, causing vibrations; accordingly, they can also affect the vestibular apparatus, which is filled with a special liquid - endolymph. For this reason, powerful bass at a certain frequency can cause headaches.
Design flaws can also cause headaches. If the headphone arch is too tight, it can cause irritation and headaches. This is a general problem with over-ear headphones that does not apply specifically to active noise cancellation. The products must be held on the head, so they should not be too weak, otherwise they will not hold on. But they should not be too tight, because constant tension can cause increased pressure. After just a few hours of listening to music in such headphones, your head will begin to hurt, and you may also feel nauseous.

What to Consider When Buying Active Noise Canceling Headphones

These headphones have a number of advantages that make them unique and modern. This includes comfort when listening to tracks and a high level of sound detail. At the same time, a safe volume level is observed that does not adversely affect the health of the hearing organs. But all these points are not a guarantee that the body will respond positively to ASP. If you don’t want to complain about a headache, you should first try the headphones of friends or acquaintances. This will eliminate the negative impact of the system on your body and general condition; for this you will need to listen to music on headphones for about 2.5 hours.

What's the result?

Headphones with active noise reduction are a convenient tool for comfortable listening to music in a modern city. They are well suited for those who are used to not parting with their favorite radio or playlist, but at the same time experience discomfort from “droplets” in the ears. They will also appeal to those who work in noisy environments, walk a lot on the street or ride the subway. At the same time, you don’t have to constantly listen to music - you can simply turn on the noise reduction system and find yourself in silence, while being in the middle of a noisy metropolis.

In general, active development is predicted for the wireless headphone segment, and the refusal of large smartphone manufacturers to use a 3.5 mm audio jack should significantly contribute to this. “Noise reduction” in such conditions can become a standard option for high-quality wireless headphones. Despite the fact that the implementation of such a system in a device, which a priori has electronic filling and batteries, does not look too expensive