About noise-canceling headphones

Noise-cancelling headphones typically use either an active or passive noise-isolation system. 

• Active Noise Cancelling (ANC) headphones were first introduced in the 1970s and work by electronically eliminating ambient noise. This is achieved through a microphone system that analyses the ambient noise and generates opposing sound waves that cancel out the noise, resulting in almost complete silence.
• Passive Noise Cancelling (PNC) headphones use a physical barrier to attenuate noise, such as the material, ergonomics, diameter, shape, fit of the headphones to achieve different levels of noise isolation.

Noise-cancelling headphones fall into four main categories: On-Ear, Over-Ear, Open-Ear and Closed-Ear.

• On-ear headphones are designed to fit over the ears and fully cover the ear cup while resting firmly on the ear. They are compact and provide good sound quality. Although they are comfortable to wear, the pressure of the pads on the ear can cause discomfort during prolonged use. These headphones are highly functional, lightweight, and easy to manage, often available in a foldable design that allows for easy storage in a backpack or bag.
• Over-ear headphones fully enclose the earcup without resting on the ear. The large padded cups on this model allow for extended wear without discomfort, and offer excellent sound quality due to better noise isolation and a wider frequency range.
• Open-ear headphones, available in on-ear and over-ear models, have a small opening (grille or perforation) in the shell housing. With this model, ambient noise can be heard and the sound from the headphones can penetrate to the outside. Although this results in less sound insulation, it offers a richer and more immersive listening experience.
• Closed headphones provide excellent sound isolation as the padded cups completely enclose the ears, preventing sound from escaping and effectively attenuating ambient noise. Whether this is an advantage or disadvantage depends on individual preferences and needs.

Different noise reduction systems have varying levels of performance and effectiveness. Complete elimination of ambient noise is not guaranteed by active noise cancellation technology.

Apart from the aforementioned systems, TWS (True Wireless Stereo) earphones can be a good option. They consist of two small separate earphones and provide high-quality sound with rich and immersive audio that is free of interference. The left and right channels are transmitted separately via Bluetooth connection using radio waves.

TWS earphones are currently very popular due to their long battery life for music playback and calls. The best TWS models in the market provide exceptional noise cancellation and wireless operation, and have a range of up to 10 meters.

There are different types of active noise-cancelling earphones on the market:

• Compact earphones: These earphones are small and offer clear sound for music and business calls without any background noise. They connect via Bluetooth and have long battery life.
• In-ear headphones: Designed for sports and physical activities, these Bluetooth headsets offer comfort, stability and protection against dust, sweat and splashing water. They also provide good noise isolation and allow freedom of movement.
• Classic in-ear headphones: These earphones have flat ear cups that rest against the ear canal, allowing ambient noise to pass through, which can affect sound quality. However, this feature can be useful when using the headphones in public places.

The essential components of noise-cancelling headphones are the driver, frequency response, and impedance.

• Driver: The sound quality of noise-cancelling headphones is heavily influenced by the driver, a disc-shaped component inserted into the earcups. It receives an electric current from the sound source and converts it into sound. The driver size, which ranges from 6 to 200 mm, plays a crucial role in determining sound quality. The most popular types of drivers used in noise-cancelling headphones include dynamic, magnetoplanar, electrostatic, and balanced-armature speakers.
• Frequency response: The frequency response refers to how the headphone receives, alters and reproduces sound frequencies from the inputs. It is a significant factor in determining how an instrument or sound is perceived. Sounds are made up of frequencies, which are then processed, modified and transmitted to the outside world. Different headphones may emphasize low or high frequencies, resulting in different sound qualities. 
• Impedance: The selection of headphones should also consider the parameter of impedance, which is the electrical resistance of a circuit when an alternating current passes through it. Impedance is measured in ohms and specified in the data sheet of all headphones. It is an important factor in determining the sound quality of headphones. Most headphones have an impedance of around 32 ohms, but high-end models can reach up to 250 ohms.

There are different types of headsets available on the market today, namely corded headsets, Bluetooth headsets and wireless headsets.

• Wired headphones: The oldest and most classic type of headphones. Wired headphones connect to a device, like a phone or tablet, through a jack socket. These type of headphones offer the best sound quality and don't need to be recharged. However, the cable can be easily damaged and limit movement.
• Bluetooh headphones: The most popular type of headphones. Bluetooth headphones connect to a desired device via Bluetooth pairing. These type of headphones are easy to connect and compatible with many different devices, making them versatile. They are affordable and suffer less from interference compared to wireless headsets. Bluetooth headphones are practical and can be used on-the-go, when commuting or exercising. However, their range is limited to about 10 meters.
• Wireless headphones: With a range of up to about 100 metres, wireless headphones offer excellent sound quality. However, they need an external transmitter to connect to compatible devices and are susceptible to interference.