How Do Bluetooth Headphones Work

Headphones are turned out to be a great blessing. Over the past decades, you will find an exponential explosion in technological innovations. Now you will find bluetooth headphones around you because many people love to use them as they offer great features.

If you are here to understand how bluetooth wireless headphones work, you will need to know how wired headsets work. In this guide, we will explain all the information that can be useful to you in order to know the working of wireless headphones.

How Do Bluetooth Headphones Work


Wireless headphones have been around since the 1960s. However, in 2004, wireless Bluetooth headphones entered the market and revolutionized personal audio listening, gaining popularity among audio users and professionals alike. If you’ve ever wondered how wireless headphones work or Earbuds play audio from your digital audio devices, this article is for you.

However, unlike wired headsets, which are physically connected to an audio source (MP3 player, smartphone, etc.), wireless headphones work by connecting and receiving electrical signals via a wireless connection between the wireless headphones and the audio source. In this way, the Bluetooth connection acts as an invisible wire and allows you to listen to music wirelessly.

Read Also: How to Make Headphones Louder

Inner Working of Bluetooth Headphones

Wireless headphones work by receiving signals sent wirelessly from the audio sources they are paired with. These signals are encoded by the source device and transmitted to radio-frequency (common) or infrared (less common) carriers. Headphones receive an RF or IR signal and decode it into audio. These are the inner functions of headphones which are given below:

1. Carrier Waves & Modulating Signals

As its name implies, modulated carrier waves carry headphone audio signals from the transmitter to the receiver. Carrier waves are electromagnetic waves that are modulated by a signal that carries information for radio transmission.

A moving electric charge generates electromagnetic waves. The vibration of an electric charge has both an electric and a magnetic component. This modulated carrier wave carries energy from one place to another. It can be heat and light from the Sun to the Earth or wireless sound from transmitter to headphone receiver.

Unlike sound waves, which are mechanical waves, electromagnetic waves can travel through space and cannot interact directly with the molecules of the medium (although the atoms inside the medium will absorb the electromagnetic wave’s energy).

Wireless headphone mount signals are usually either radio waves (normal) or infrared waves (rare). Radio frequencies (RF) cover a wide range from 30 Hz to 300 GHz (300,000,000 Hz). The infrared (IR) frequency range is from 300GHz to 430 THz.

Whether the headphones use RF or IR, the carrier wave is a sine wave with a signal frequency. The transmitter is set to transmit a single frequency carrier, and the receiver is set to accept a single frequency carrier.

2. Wireless Analog Audio Transmission

To transmit wireless analog audio signals in headphones, this is the most common frequency modulation. FM radio uses the same transmission, which basically displays RF FM headphones as mini radio stations!

Frequency modulation (FM) works by converting the frequency of a carrier’s width into a modulating signal. If we send a simple audio sine wave, the resulting frequency-modulated signal will look like this:

Therefore, a “single-frequency” carrier wave, once modulated by the audio signal, must actually operate within a range of frequencies. The receiver is designed to accept carrier bandwidth.

To reduce and shorten the carrier-width frequency difference, the audio signal is amplified only after the headphone receiver is demodulated.

3. Wireless Digital Audio Transmission

With the advent of digital audio and digital audio devices, many headphones are now designed to accept digital audio wirelessly. Digital audio is basically a digital representation of analog signal audio.

Analog sound consists of continuous waves of alternating current. Digital audio basically takes a real-time snapshot of the audio signal amplitude and represents it digitally.

Digital audio quality can be determined by sample rate and bit depth.

Sample rate refers to the number of individual sound amplitudes per second. Typical sampling rates include 44.1 kHz and 48 kHz. In this case, Hz means sample/second.

Bit depth refers to the number of bits used to represent the dimensions of any given pattern. Bits refer to the number of binary digits (1 and 0) tied together to represent a value. Simple bit depth consists of 16 bits (contains 65,536 distinct values) and 24 bits (contains 16,777,215 distinct values).

The higher the sample rate and bit depth, the higher the resolution, and in theory, the higher the quality of the digital audio signal. Note that higher sampling rates and slightly deeper depths also require more processing power and that different sampling rates are incompatible with each other.

Modules of a Bluetooth headphone

Knowing what Bluetooth headphones are, it can be explained further how wireless headphones work. The main components inside Bluetooth headphones are like wired headphones. These include magnets, a sound coil, and a diaphragm. These components together make up the engine unit.

In addition, both wired and wireless headsets are equipped with a microphone that allows you not only to listen to music but also to record your voice and talk to other people and digital to analog conversion.

In addition to the components that produce sound, wireless headphones also have components that help them function properly. It includes a rechargeable battery, a Bluetooth system (SoC) on a chip, and a digital to analog converter (DAC).

The main components of the Bluetooth headset and their functions are described below.

  1. Driver unit
  2. Rechargeable battery
  3. System on a chip

1. Driver unit

The driver unit inside the wireless headset is the part that actually produces the sound. Thus, it is the transducer that is responsible for converting the electrical signals it receives into sound. The motor unit can be of different types depending on the transducer technology you are using.

The most commonly used drive unit is known as a “dynamic” driver or moving coil motor. It consists of a ferrite or neodymium magnet, an acoustic coil, and a cone (membrane). A sound coil is a coil of conductive wire (copper) attached to a diaphragm. Typically, the sound coil is suspended in the magnetic field of a permanent magnet.

However, when it receives an audio signal in the form of an electric current, the sound coil becomes an electromagnet and initiates a permanent magnetic push and pull game, causing the diaphragm to vibrate. As the graph is exposed to air, the vibrations of the air around the diaphragm follow the rhythm of the diaphragm and produce sound waves.

The intensity and frequency of vibrations depend on the properties and strength of the audio signal received. In addition to “dynamic” drivers, headphones can have other types of driver units such as static electricity, planar magnetism, electrostatic, iron balanced, etc. Wireless headphones and wired headphones use the same type of driver unit to create music.

2. Rechargeable battery

Unlike wired headphones, bluetooth headphones require a battery to operate. The battery enables the community inside to connect with other Bluetooth devices, process digital signals, convert them to analog signals, use noise-canceling features, and more.

The internal battery must be powered to keep the headphones “wireless”. These can be AA or AAA batteries or the battery inserted into the headphones. However, it is common for today’s wireless headphones work to have built-in rechargeable batteries. The device has a charging port so you can charge a rechargeable battery if needed.

3. System on a chip

Bluetooth headsets consist of a system on a chip (SoC) consisting of an integrated circuit with a digital signal processor (DSP), a digital-to-analog converter (DAC), memory, a communication port, a microcontroller, and a Bluetooth hardware unit. Comes with a microprocessor. happen, etc.

A Bluetooth hardware module is a component that enables Bluetooth communication. Every Bluetooth-enabled device, such as a smartphone or smart TV, has a Bluetooth hardware module inside. The Wireless Bluetooth headsets module consists of two parts: a radio and a digital signal console.

Simply put, the digital console acts like a CPU to control various Bluetooth functions. The radio equipment acts as a transmitter of radio signals as well as a receiver of a radio audio signal.

Wired headphones usually don’t have a DAC & amp because the signal they receive is actually converted by the DAC & amp inside the music source. The exception is wired headphones that use a USB Type-C or Lightning port.

Wireless headphones have a built-in DAC and MPS because the Bluetooth signal from the audio source transmits data digitally and needs to be converted into an analog signal to make music.

How Does Bluetooth Headphones Works Technically?

Wireless headphones work just like any other Bluetooth device. It is a wireless technology that uses Ultra High Frequency (UHF) radio waves to transmit data over short distances in the Industrial, Scientific, and Medical (ISM) radio bands from 2.400 to 2.485 GHz.

Bluetooth wireless devices do not require a lot of power to transmit data because the data is transmitted by low-energy radio waves. So even a low-capacity battery can power for hours and your wireless headphones work.

All bluetooth devices can be divided into 3 categories. Each class is rated according to its maximum strength and permissible limit. Wireless headphones are Class II devices with a range of up to 10 meters and maximum power consumption of 2.5 mm.

Data is transmitted between wireless headphones and an audio source using long-distance wireless or radiant energy transfer technology. Basically, each Bluetooth device has a receiving antenna and a transmitting antenna.

When your wireless headphones work by receiving a digital audio signal and are securely connected to your smartphone or other audio sources, they become the receiver of all wireless data that can be transmitted through the audio source.

Once you start playing music from your smartphone or other sound sources, the transmitter converts the signal or electrical energy over time into various electromagnetic fields (a wireless signal) that can travel through space.

This wireless signal is then picked up by the receiver inside your bluetooth wireless headphones. The receiver then draws energy from the electromagnetic field and distributes it to electrical components inside the device that use the power.

The Bluetooth Special Interest Group (SIG) has a Bluetooth standard which is expressed in the release. Currently, 5.1 is the latest version of bluetooth and it offers the best features and functions. In addition, all versions are backward compatible. Therefore, it is recommended to buy wireless headsets that support the latest Bluetooth version.

Do Bluetooth Headphones Work Similarly to Wi-fi headphones?

A common question that people ask is why are wireless headphones more popular than wifi headphones. Although there are some similar applications for Wi-Fi and Bluetooth and they mostly use the same radio frequency band for data transfer, they are designed for different applications and are suitable for different purposes.

Wi-Fi is an alternative to high-speed Internet connections and is one of the wireless transmission methods of the audio signal over a wired network, while Bluetooth is an alternative to wires for wireless connections to various devices. Thus, although Wi-Fi radio frequency data transfer rates are much better than Bluetooth, the newer ones are more energy-efficient and cheaper.

Another fact to consider is that Bluetooth is less intrusive than Wi-Fi. Bluetooth devices transmit data using a method called diffuse frequency hopping. Basically, Bluetooth devices transmit data after splitting it into multiple packets.

Each packet is randomly transferred in a short burst over 79 distinct Bluetooth channels, each with a bandwidth of 1 MHz. This hopping is 1,600 times per second. In addition, the speed of data transmission via Bluetooth is, in most cases, sufficient to listen to music without buffering.

Thus the bluetooth device changes the channel every 625 microseconds. Since a Bluetooth device does not stay on a particular channel as long, it has a lower risk of intrusion problems than other Bluetooth or Wi-Fi devices, unlike Wi-Fi devices. In addition, RF wireless headphones offer an additional layer of security so as to not get hacked.

Are Bluetooth Headphones Safe to Use?

Many people are concerned about the potential effects of Bluetooth headphones on our health. This is a valid concern as Bluetooth headphones will be worn over your head when in use and can be worn around your neck when not in use.

Bluetooth headphones work on the same principles as cell phones, Wi-Fi devices, and other wireless devices that use radio waves to transmit data. Thus, these devices emit an electromagnetic radio, which, according to the International Agency for Research on Cancer (IARC), can cause cancer. However, as of 2019, there are no reports of any health injury specifically due to the use of Bluetooth technology.

The level of damage to our body depends on how much energy the device transmits. To understand how much you are affected by the radiation emitted by Bluetooth headphones, let’s compare it with a mobile phone that is used by almost everyone in this age group.

Compared to cell phones that transmit data over long distances (km), Bluetooth headphones have to transmit data within a range of 10 meters or 30 feet. Therefore, it requires much less power than a smartphone to transmit data.

To put this in perspective, Bluetooth headphones, which are Class 2 devices, can transmit up to 2.5 mW of power. Mobile phones operating in the GSM 850/900 frequency band generate 2,000 MW of power.

If you’re still unsure, you can check their specific absorption rate (SAR) when buying your Bluetooth headphones and avoid using them for a long time.

How Secure are Bluetooth Headphones?

Devices that transmit data wirelessly are less secure than devices that transmit data over a wired connection. Bluetooth headphones are the same. The security of Bluetooth devices has improved over the years.

With the release of new versions and the introduction of new security features, threats such as “Blue Jacking” or “XOR” attacks are no longer an issue. You can set the wireless headphones to “ignore”. This will act as the first layer of protection.

Pairing a wireless headphone is another layer of protection. In addition, the frequency hopping spread spectrum technology used by Bluetooth devices adds an extra layer of security.

However, if the hacker has the right tools and knowledge, he can gain access to your data or take control of your device. However, this applies to every wireless technology, including Wi-Fi, which is not easy at all. Bottom line, you shouldn’t worry too much about it.

How do Bluetooth Codecs Affect the Audio Quality?

By general consensus, wired headphones provide better sound quality than wireless headphones. While this is true, in recent years, modern technology has greatly improved the sound quality of Bluetooth headphones.

In fact, if you choose high-quality wireless headphones, you won’t notice any difference in sound quality unless you’re born with “golden ears,” signal out of range and out of range. there are problems.

Most people only look at speaker or driver features when buying Bluetooth headphones. However, other factors such as the DAC and the Bluetooth codec it supports can also affect sound quality. The quality of the DAC in a wireless headset can affect the quality of the sound you hear.

Another factor to consider is sound pressure. The data transfer rate of Bluetooth headphones can become unstable when exposed to interference. In addition, the data transfer speed is slow compared to other types of wireless communication.

This can cause a lot of trouble while listening to music. To solve this problem, the data is compressed to reduce the file size and data transfer time. However, the lost audio file doesn’t sound good.

Advanced audio coding algorithms developed by the developers help to tackle the problem of compression without compromising on the audio quality. The different Bluetooth codecs are shown below:

  • SBC
  • Qualcomm’s proprietary codecs (aptX, aptX HD, aptX LL)
  • AAC
  • LDAC

1. SBC

This Subband is an acronym for the codec. The least complex codec subband is the Universal codec because it is supported by all A2DP-enabled devices. However, it is a malicious compression algorithm that loses bits of low-priority information during playback. Thus, due to significant data loss, the sound quality drops significantly. Transfer rates can range from 192 to 320 kbps.

2. Qualcomm’s proprietary codecs

The proprietary codecs developed by Qualcomm have greatly improved the quality of music running over Bluetooth technology. For this reason, it has been widely adopted by many smartphone brands such as Microsoft, LG, Xiaomi, etc. Here are the codecs developed by Qualcomm:

aptX: This is the simplest aptX codec. It supports 48kHz/16bit LPCM (Liner Plus Code Modulation) audio data (352kbps). This codec is designed to provide “CD-like” audio quality via Bluetooth technology.

aptX HD: aptX HD uses “soft” compression to transmit 24-bit/48 kHz audio at a rate of 576 kbps. Although both aptX and aptX HD formats are harmful, they sound much better than SBC and can stream high-quality audio without any hesitation or delay.

aptX LL: aptX LL supports a 40ms delay and can transmit 48kHz/16bit LPCM audio data. This codec is designed to reduce sync issues when watching video or gaming.

3. AAC

It stands for Advanced Audio Coding and is the standard for lossy digital audio compression. It can transmit audio data at 250 kbps and is highly compatible with Apple.


It is a proprietary codec developed by Sony that supports 3 times more data than SBC. Supports 96/kHz/24bit at max 990kbps.

As such, to ensure that you can listen to the best music in high quality on your Bluetooth headphones, make sure that they support any modern codec such as aptX. You should also note that both your Bluetooth headphones and your audio source must support the latest codecs to produce better quality audio.

Frequently Asked Questions

How do wireless bluetooth headphones work?

Wireless headphones are connected or paired to the device you want to use via radio or infrared signal. Many devices use Bluetooth technology to make communication easier for the user. Devices with Bluetooth technology can communicate and exchange data over very short distances using wireless transmission.

Do you need Wifi for bluetooth headphones to work?

In order to use bluetooth headphones, there is no need of Wifi connection. All you need is to make sure that your device has bluetooth enabled.

Do bluetooth headphones work with any phone?

All versions of Bluetooth are backward compatible. This means that any Bluetooth headphone will work with any phone, regardless of the version. The base Bluetooth headphones will work with the latest versions of Bluetooth and is usually compatible with older phones that use the previous generation of Bluetooth.


This was all about how does bluetooth headphone works. I hope that you have understood the working of headphones. We have provided you with the inner working as well as some technical details about headphones work.

What do you think about this guide which is about bluetooth headphones working? Have you learned something new by reading this article? If yes, let us know in the comment section.


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