How effective are noise-canceling headphones? Are they truly noise-canceling or just a waste of money?

The rapid development of science and technology has brought not only a convenient and fast lifestyle, but also noise pollution, which is an issue that cannot be ignored in contemporary society. Although the country has issued a series of relevant standards and has clear requirements for noise, various noises surrounding daily life are still unavoidable - traffic noise from cars and airplanes; industrial noise from construction sites and equipment operation; and advertising noise in the streets and alleys, noisy and noisy life noise...

The harm of noise to the human body cannot be underestimated. In a continuous strong noise environment, it will not only affect people's sleep quality, but also damage people's hearing and even cause damage to people's nervous system, such as dizziness, etc., which will cause some irreversible harm.

So people choose to use headphones to block out noise. But ordinary headphones can only cover up noise by physically reducing noise or increasing the volume. Little do they know that this will not only make it impossible to listen to beautiful music, but will also have a certain negative effect on their own hearing. At this time, the emergence of noise-canceling headphones is particularly important. However, when faced with such equipment, people always have doubts, fearing that they are paying an IQ tax. Why not analyze it together!

Headphones that can effectively reduce external noise are called noise-canceling headphones. Based on the design principles, they are mainly divided into two categories, namely active noise reduction and passive noise reduction.

Passive noise cancelling headphones

Passive noise-cancelling headphones are low-cost and the easiest noise-cancelling technology to implement. They are more common in daily life, such as in-ear headphones that are tightly coupled to the human ear, and headphones that cover the human ear... But whether it is in-ear or head-mounted, earmuffs are an important factor affecting their passive noise-cancelling capabilities.

The noise reduction principle of passive noise reduction headphones is simple and crude, mainly through physical isolation or using the special structure of the headphones to absorb and block noise as much as possible. Because of this, high-density isolation materials are used in terms of materials, so the headphones will be slightly heavy, and wearing them for a long time will have a certain impact on comfort. Moreover, it has great limitations. Passive noise reduction headphones are mainly aimed at high-frequency noise pollution. For noise pollution below 800Hz and lower frequency bands, if you want to achieve the best ideal effect, you will need to pay a higher cost. At the same time, the noise reduction material inside the headphones will be heavier, which will lose its practical significance.

Active noise cancelling headphones

Active noise reduction headphones can completely solve the problems of passive noise reduction headphones, mainly to eliminate low-frequency short noise pollution. It has a system inside to eliminate noise......

You should know that sound is composed of a certain spectrum and energy. The principle of active noise-cancelling headphones is that the internal system collects and analyzes noise, and then uses the built-in circuit to actively generate a sound with a spectrum that is exactly the same as the noise to be eliminated and the opposite phase, so that it can be superimposed, interfered with, and eliminated with the noise in a specific space.

At present, according to the working principle and design structure of active noise reduction headphones, they can be divided into two types: feedback type and feedforward type. Both feedforward and feedback active noise reduction headphones contain a microphone and a secondary sound source.

The microphone is responsible for collecting noise. Some composite active noise reduction headphones also have two microphones, one for collecting external noise, called the reference microphone, and the other for collecting internal noise, called the error microphone. In view of the actual application scenario requirements of active noise reduction headphones, the microphone should have the characteristics of small size, high sensitivity, and good frequency response.

Secondary sound sources mainly refer to various types of speakers, which mainly convert electrical energy into sound and can radiate sound energy.

The external microphone of feedforward active noise reduction headphones usually faces outward and collects external environmental noise through the sound-permeable holes of the headphones. When the external microphone collects the noise signal, it transmits it to the secondary sound source through the ANC control circuit without a feedback loop. However, it will have a good noise reduction effect on stable noise, but the scope of application will be greatly limited, and it will usually only appear in low-end headphone products.

The internal microphone of feedback-type active noise reduction headphones is inside the headphones, usually placed at the entrance of the ear canal. When the internal microphone collects the noise entering the headphones, it will generate a secondary sound signal with opposite phase, equivalent amplitude and equal frequency through the ANC noise reduction processing circuit, and finally transmit it to the secondary sound source, which releases noise with opposite phase, thereby realizing active noise reduction operation. The internal microphone of feedback-type active noise reduction headphones is usually near the secondary sound source, which can more realistically reflect the noise felt near the hearing, so the noise reduction effect will be better, but the internal structure will be relatively complicated.

Among the many active noise-cancelling headphone products, the quality of relevant technology is an important factor in ensuring the active noise-cancelling effect. Of course, in addition to quality, price and compatibility are also important issues that consumers need to consider.