How Do Bluetooth Headphones Work? (Everything You Wanted To Know)

Bluetooth headphones have grown in popularity in recent years due to the convenience they provide. Although wired headphones are still widely used, an increasing number of people are opting for wireless headphones that connect to an audio source via Bluetooth technology.

The question is: How do Bluetooth headphones work?

Before we begin, you should be aware that not all wireless headphones make use of Bluetooth technology. Some wireless headsets operate using Wifi, infrared, or other radio technology.

To understand how Bluetooth headphones work, you must first understand how speakers and wired headphones work. Once you understand how these devices function, you will be able to comprehend how Bluetooth headphones, headsets, or earphones function.

Video: How Do Bluetooth Headphones Work?

Here is a short video of how Bluetooth headphones work.

HOW DO HEADPHONES WORK?

In essence, any type of headphones or speaker serves as an electroacoustic transducer. As a result, these contain components within them that can convert the electrical energy received from the sound source into sound energy (sound waves) that we can perceive as music.

Bluetooth headphones function almost identically to standard headphones. As a result, they convert electrical signals to sound waves.

Unlike wired headphones, which physically connect to the sound source (mp3 players, smartphones, etc.) via the headphone jack and receive the electrical signal via the headphone wire, Bluetooth headphones connect wirelessly to the sound source via Bluetooth technology and receive the electrical signal via the wireless connection established between the Bluetooth headphones and the sound source.

As a result, the Bluetooth connection functions as an invisible wire, allowing you to listen to music wirelessly. That is the primary distinction between a wired and a Bluetooth headset.

After receiving a wireless signal, a Bluetooth headphone converts it back into an electrical signal, which is then converted into sound energy by the small speakers or driver units housed inside the headphones.

THE COMPONENTS OF A BLUETOOTH HEADPHONE

Knowing what Bluetooth headphones are made of can further clarify how they function. The main components that generate sound inside Bluetooth headphones are the same as those found in wired headphones.

Magnets, voice coils, and diaphragms are examples of these. These components, when combined, form the driver unit. Furthermore, both Bluetooth and wired headsets include a microphone, allowing you to not only listen to music but also record your voice and converse with others.

Bluetooth headphones, in addition to the components that produce sound, contain components that aid in the proper operation of the device.

A rechargeable battery, a Bluetooth system on a chip (SoC), and a digital-to-analog converter are among them (DAC). The following sections describe the main components of Bluetooth headphones as well as their functions.

1. Driver Unit

The driver unit inside a headphone is the part that actually produces the sound. Thus, it is the transducer responsible for converting the electrical signals it receives to sound. The driver unit can be of different types depending on the transducer technology it utilizes. 

A ‘dynamic' driver, also known as a moving coil driver, is the most commonly used type of driver unit. A ferrite or neodymium magnet, a voice coil, and a cone make up the device (diaphragm). The voice coil is a copper-coated wire coil that is attached to the diaphragm.

Normally, the voice coil remains suspended in the permanent magnet's magnetic field. When it receives an audio signal in the form of an electric current, the voice coil transforms into an electromagnet and begins a tug-of-war with the permanent magnet, causing the diaphragm to vibrate.

When the diagram comes into contact with air, the air around the diaphragm begins to vibrate in time with the diaphragm and produces sound waves. The characteristics and power of the sound signals it receives determine the intensity and frequency of vibration.

Aside from ‘dynamic' drivers, headphones can also have electrostatic, planar magnetic, electret, balanced armature, and other types of driver units. Bluetooth and wired headphones use the same types of driver units to produce music.

2. Rechargeable Battery

Bluetooth headphones, as opposed to wired headphones, require batteries to operate. The battery powers the Soc inside the device, allowing it to connect to other Bluetooth-enabled devices, process and convert digital signals into analog signals, use noise-cancellation features, and so on.

The device also has a charging port, allowing you to charge the rechargeable battery when needed.

3. System On A Chip

Bluetooth headphones include a system on a chip (SOC), which is an integrated circuit that includes the Bluetooth hardware module as well as a digital signal processor (DSP), a digital-to-analog converter (DAC), and memory, connection ports, microcontrollers, microprocessors, and other components.

Bluetooth hardware modules are components that enable Bluetooth communication. Every Bluetooth-enabled device, such as a smartphone or smart television, contains a Bluetooth hardware module. A Bluetooth hardware module is made up of two components: a radio device and a digital controller.

Simply put, the digital controller functions as a CPU to control the various Bluetooth functions that it supports. The radio device functions as both a transmitter and a receiver of radio signals.

Wired headphones typically lack a DAC and amp because the signal received is already converted by the DAC and amp built into the music source.

Wired headphones that use the USB type-c or lightning port are an exception. Bluetooth headphones include built-in DACs and amplifiers because the Bluetooth signal received from the sound source transfers data digitally and must be converted into an analog signal to produce music.

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DO BLUETOOTH HEADPHONES WORK SIMILARLY TO WI-FI HEADPHONES?

People frequently wonder why Bluetooth headphones are more popular than Wi-Fi headphones. Although Wi-Fi and Bluetooth have some similar applications and primarily use the same radio band and frequency to transmit data, they are designed for different applications and are best suited for different purposes.

Wi-Fi is intended to be a replacement for a high-speed internet connection on a wired network, whereas Bluetooth is intended to be a replacement for wires for wirelessly connecting to various devices.

As a result, while Wi-Fi data transfer rates are far superior to Bluetooth, the latter is far more power-efficient and less expensive. Furthermore, in most cases, Bluetooth data transfer speed is sufficient for listening to music without buffering.

Another thing to remember is that Bluetooth technology suffers from less interference than Wi-Fi technology. Bluetooth devices use a technique known as frequency-hopping spread spectrum to transmit data.

Bluetooth devices, in essence, transmit data after dividing it into several packets. Each packet is sent at random in short bursts across 79 Bluetooth channels, each with a bandwidth of 1 MHz. This hopping occurs at a rate of 1600 times per second.

As a result, a Bluetooth device changes channels every 625 microseconds. Because a Bluetooth device does not stay on a specific channel for long periods of time, it is less prone to interference problems caused by other Bluetooth or Wi-Fi devices, unlike a Wi-Fi device. Furthermore, it adds an extra layer of security.

HOW DO YOU CONNECT BLUETOOTH HEADPHONES WITH A SMARTPHONE?

Just like any Bluetooth device, it is fairly easy to connect a Bluetooth headphone with your smartphone. To connect your Bluetooth headphones, all you have to do is follow the instructions listed on the user manual that came with the product. A brief overview of the general steps is listed below:

1. Turn on Bluetooth on your mobile device by going to the Bluetooth settings menu.

2. To put your Bluetooth headphone into the ‘discoverable' mode, follow the instructions in the product guide.

3. When your mobile device detects the Bluetooth signal emitted by your Bluetooth headphones, you can begin the pairing process. When connecting for the first time, you only need to pair the two devices. You must enter a PIN number to pair both devices. In most cases, the default PIN number is 0000. If it doesn't work, consult your product manual.

4. Once both the devices are paired, you can start using your Bluetooth headphones to listen to music anytime you want.

ARE BLUETOOTH HEADPHONES SAFE TO USE?

Many people are concerned about the health effects of Bluetooth headphones. This is a legitimate concern because Bluetooth headphones are worn over your head when in use and may be worn around your neck when not in use.

Bluetooth headphones operate on the same principles as cell phones, Wi-Fi devices, and other wireless devices that transmit data via radio waves.

As a result, these devices emit electromagnetic radio waves, which the International Agency for Research on Cancer (IARC) believes may be carcinogenic. However, as of 2019, there have been no reports of people suffering from health problems as a result of using Bluetooth technology.

The amount of power transmitted by the device determines the level of harm that may be done to our bodies. To understand how much radiation emitted by Bluetooth headphones can affect you, consider comparing it to a mobile phone, which almost everyone in this day and age uses.

In comparison to cell phones, which must transmit data over long distances (kilometers), Bluetooth headphones must transmit data over short distances (up to 10 meters or 30 feet). As a result, it requires far less power than smartphones to transfer data.

To put this into perspective, Bluetooth class 2 headphones can transmit up to 2.5 mW of power. Mobile phones that operate on the GSM 850/900 frequency band produce 2000 mW of power.

If you are still unsure, you can check the specific absorption rate (SAR) of your Bluetooth headphones when purchasing them and avoid using them for long periods of time.

HOW SECURE ARE BLUETOOTH HEADPHONES?

Wireless data transfer devices are less secure than wired data transfer devices. Bluetooth headphones are interchangeable. Bluetooth device security has improved over the years.

Threats such as ‘Bluejacking' or ‘XOR' attacks are no longer a concern with the release of new versions and the implementation of new security features. Keep your Bluetooth headphones in ‘undiscoverable' mode.

This will serve as the first line of defense. Bluetooth headphones' pairing mechanism is the second layer of security. Furthermore, Bluetooth devices use a frequency-hopping spread spectrum technique, which adds an extra layer of security.

Still, if a hacker has the right tools and knowledge, they may be able to get access to your data or control your device. However, this is true for every wireless technology including Wi-Fi, and not easy at all. Bottom line, you should not worry too much about it.

BLUETOOTH CODECS AND HOW THEY AFFECT AUDIO QUALITY

Let us now address the elephant in the room: sound quality. We purchase headphones to listen to music. As a result, the most important factor that we all look for when purchasing a pair of headphones is sound quality.

According to most people, wired headphones have better sound quality than wireless headphones. While this is true, modern technology has greatly improved the sound quality of Bluetooth headphones in recent years.

In fact, unless you have a ‘golden ear,' are out of signal range, or are suffering from interference issues, you will barely notice the difference in audio quality if you choose a good quality wireless headset.

Most people only look at the specifications of the speaker or driver unit when buying Bluetooth headphones. However, other factors such as the DAC and the Bluetooth codec it supports can affect the sound quality as well.

The quality of the DAC present in a wireless headphone can affect the quality of the sound you listen to in the end.  Another thing to consider is audio compression. When Bluetooth headphones are subjected to interference, their data transfer rates can become unstable.

Furthermore, data transfer is slower than with other types of wireless connections. This can lead to a slew of issues when listening to music. To address this issue, data is compressed to reduce file size and data transfer time. A lossy audio file, on the other hand, does not sound as good.

Developers' advanced audio codec algorithms aid in addressing the problem of compression without compromising audio quality. The following are the different types of Bluetooth codecs:

1. SBC

This is an abbreviation for Subband Codec. Because it is supported by all A2DP-enabled devices, the low-complexity Subband codec is a universal codec.

However, it is a lossy compression algorithm that drops low-priority information during playback. As a result of the significant data loss, the sound quality suffers greatly. The transfer rate can range between 192 and 320kbps.

2. Qualcomm’s Proprietary Codecs

Qualcomm's proprietary codecs have significantly improved the quality of music streamed over Bluetooth. As a result, it has been widely adopted by various smartphone brands such as Microsoft, LG, Xiaomi, and others. Qualcomm has created the following codecs:

• aptX is the most basic aptX codec. It accepts audio data at 48 kHz/16-bit LPCM (Linear Pulse Code Modulation) (352 kbps). This codec was created to provide ‘CD-like' audio quality via Bluetooth.

• aptX HD – The aptX HD uses a ‘gentle' compression method to send 24-bit/48kHz audio at 576 kbps. Despite the fact that aptX and aptX HD are both lossy formats, they sound significantly better than SBC and can stream higher quality audio without stuttering or latency.

• aptX LL – The aptX LL supports a latency of 40ms and can transmit 48kHz/16bit LPCM audio data. This codec was designed for reducing syncing problems when watching videos or gaming.

3. AAC

This abbreviation stands for advanced audio coding, which is the industry standard for lossy digital audio compression. It is most compatible with Apple and can transmit audio data at a rate of 250 kbps.

4. LDAC

This is Sony's proprietary codec, which supports up to three times the data of SBC. It can handle 96/kHz/24-bit data at a maximum of 990kbps. As a result, if you want to listen to high-quality music on your Bluetooth headphones, make sure they support advanced codecs like aptX.

It's also worth noting that in order to reproduce higher-quality sound, both your Bluetooth headphones and your audio source must support advanced codecs.

FAQs About Bluetooth Headphones