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Bluetooth Technology in Headphones

Last updated: 4 months ago
6 min read

Everything you need to know about wireless Bluetooth technology in headphones.

Bluetooth headphones on colorful rocks.
Table of Contents

    What is Bluetooth?

    Bluetooth is a wireless technology for data exchange over short distances among electronic devices using UHT radio waves (the science behind it).

    The standard range is up to 33ft (10m), and the Bluetooth 5.0 can reach around 100ft (40m). It’s used by many devices such as smartphones, personal computers (mostly laptops), TVs, car radios, speaker systems, and headphones.

    The Bluetooth Special Interest Group (Bluetooth SIG) oversees the development of Bluetooth standards and gives licenses to manufacturers to use the technology in their products.

    The Latest Bluetooth Versions and What It Means for You

    In the past years, we got 3 different versions of Bluetooth: 5.05.1, and 5.2.

    Bluetooth 5.2

    LE Audio (LC3 Bluetooth codec)

    This is a new generation of low-energy audio that expands on existing functions. It offers variable (and higher) transfer speeds while keeping power consumption down.

    The secret is in much more efficient compression on a transmitting side and decompression on receiving side. The new Bluetooth codec will replace SBC as a new standard.

    Enhanced attribute protocol

    Previously, multiple apps on a transmitting device communicated with a receiving device in a sequential manner (when one is speaking, others are blocked).

    With Bluetooth 5.2, they can do it simultaneously.

    Isochronous channels

    This feature allows you to connect your headphones to multiple devices at once and seamlessly switch between each other.

    Meaning if you’re listening to TV via Bluetooth and someone phone calls, headphones will automatically switch to your phone.

    Furthermore, it will help users with hearing aids. It allows audio sharing from a TV, giving you the option to boost loudness independently. That way, you don’t bother everyone around with loud TV.

    Hearing aid
    Bluetooth devices with version 5.2 can now offer many useful features, even for users with hearing problems.

    Potentially, you will even walk into a bar, see a football match on a TV, and tune your headphones to a specific channel to hear a commentator more clearly.

    Listeners will have the ability to select commentators in different languages (if the audio stream contains such data).

    There’s also support for multiple audio broadcasting to different headphones. You can even send different audio streams to the left or right wireless earbud.

    Bluetooth 5.1

    Accurate location tracking

    Version 5.1 requires having more antennas placed around a transmitting device. By checking Bluetooth signal strength in each antenna (“angle of arrival” and “angle of departure”), it can more accurately determine the location of receiving device.

    This feature comes in handy for tracking lost gadgets.

    Lady listening to wireless headphones

    GATT caching

    GATT caching speeds up the process of pairing two Bluetooth-enabled devices that were previously already connected. Since they already know their pairing information, they skip the identification procedure. As a result, they save on battery.

    Connection advertising

    Two things are new: “randomized advertising channel indexing” and “periodic advertising sync transfer.”

    The first one is a way Bluetooth cycles between channels.

    Since Bluetooth runs on the 2.4GHz frequency, each wireless device uses channels to avoid interferences.

    Previously, it cycled in exact order. With Bluetooth 5.1, it picks up the channel randomly, which improves connection stability.

    The second feature gives all Bluetooth devices in your home the ability to share advertising schedules. That makes pairing faster, even with new devices.

    You can read a more detailed comparison between Bluetooth 5.0 and 5.1 here.

    Bluetooth 5.0

    BLE (Bluetooth Low Energy)

    This feature was already available in Bluetooth 4.0 for trackers, but with Bluetooth 5.0, you can also use it with headphones. That means lower power consumption on both transmitting and receiving devices.

    Wider Bluetooth range

    The four-times wider range over the previous generation means that, theoretically, Bluetooth 5.0 can reach up to 800 feet (240 meters) in radius.

    Higher transfer speeds

    Data transfer doubled, from 1Mbps to 2Mbps. That comes in handy for Dual Audio features and high-res audio.

    Dual Audio

    Now you can connect two devices and use them at the same time. You can either connect two headphones or two speakers (creating stereo mode).

    How is Bluetooth Technology Used in Wireless Headphones?

    With the advent of smart mobile phones with Bluetooth technology and fast-speed mobile internet with music streaming services like Spotify, Bluetooth headphones have become more popular.

    In the past, wires were the only way to connect your pair of headphones to a mobile phone or tablet. Today, Bluetooth headsets offer more convenience and a wire-free experience that’s preferred by many.

    You can get them at an affordable price that compares to wired headphones.

    Add the absolute freedom you experience with the latest true wireless earbuds, and you’ll understand why wireless headphones are storming the market.

    True wireless buds are super easy to use.

    After the first Bluetooth connection is established, the Bluetooth headphones connect automatically when turned on. It takes even less work than putting in the wires.

    You also get built-in or in-line remote controls for changing songs, volume, and answering calls as a standard feature.

    But, since Bluetooth needs power, you need to charge the battery every once in a while. Thankfully most Bluetooth headphones offer a decent battery life.

    20 – 40 hours for over-ear and on-ear headphones and around 10 hours for in-ears (earbuds).

    Charging up is pretty quick, with the usual time around 2 hours for a full charge. Also, the newest USB-C charging is even faster, and some headphones with quick charging can last over an hour after a short 5-minute power-up.

    How High-Quality is Audio Transmitted via Bluetooth?

    The sound quality of audio transmitted via Bluetooth is dependent on the Bluetooth codec that’s in use.

    Note: both the mobile device and the headphones need to support the Bluetooth codec you want to use.

    The usual rule is, higher the bit rate, the better the sound quality.

    SBC – First and most common is SBC or sub-band codec that is mandatory to be included in all Bluetooth-supported headphones and speakers (with A2DP profile).

    It offers reasonable audio quality at average bit rates and low processing demands. It’s capable of 345 kbps bit rate and sample rate up to 48 Hz (though you’ll usually get less). It doesn’t offer the best sound quality but works with every Bluetooth device.

    aptX – This is a family of Bluetooth codecs made by a giant Qualcomm that improves overall wireless Bluetooth connectivity. These are probably the most popular non-mandatory codecs.

    They make classic aptX codec, aptX Low Latency (aptX LL) that shortens the audio delay when watching videos, aptX HD that offers the highest bit rate and sound quality in the group, and the latest aptX Adaptive that adapts to the needs at hand.

    LDAC – It’s made by Sony, has a variable bit rate, and is now supported on most Android devices (after Oreo).

    It features 3 different modes, one with a bit rate of 330 kbps (Connection), the second with 660 kbps (Normal), and the best at massive 990 kbps (Priority). The codec changes modes automatically depending on connection quality.

    LDAC is capable of high-resolution audio wireless transmission with a small loss in quality.

    AAC (Advanced Audio Coding) – It’s an audio coding international standard for digital compression with some loss in quality (replacement for MP3).

    It’s supported by many devices, including iOS devices (iPhone, iPad, iPod), Blackberry, and Android smartphones. It’s also the default standard on YouTube. AAC is capable of high audio quality at lower bit rates than MP3.

    But compared to SBC and aptX, it usually performs worse. Furthermore, iPhones offer better sound with AAC than Android phones because of how battery functions are programmed.

    How Did Bluetooth Get Started?

    Ericsson R520m
    Ericsson R520m was the first cell phone with Bluetooth.

    The short-range radio technology, later named Bluetooth after the king Harald Bluetooth, was initially developed in 1989 in Sweden.

    It was released to the market in 1999 as the Bluetooth 1.0. And, the first Bluetooth cell phone was released in 2001 as the Ericsson R520m. More history of Bluetooth.

    Advancement of Bluetooth Technology in Headphones

    Bluetooth wireless connectivity
    Different wireless devices are connected to a Bluetooth network.

    What was the First Pair of Bluetooth Headphones?

    Nobody really knows what the first Bluetooth headphones were, but they were released in 2004, according to the official Bluetooth page.

    Nonetheless, wireless Bluetooth headphones became a practical option in the 2010s and a popular option a couple of years ago (with efficient Bluetooth codecs).

    What are the Previous Limitations of Bluetooth that Have Been Improved Over the Years?

    The biggest limitation was the sound quality and audio delay.

    When you use Bluetooth to transmit audio over the air (radio frequencies), it needs to encode the analog signal into a digital signal to send over.

    On the receiving side, a DAC decodes digital audio signals back to analog.

    In the process, some of the musical data is lost. Hence the loss in audio quality.

    Right now, any headphones with Bluetooth slightly corrupt the music quality even if you send them high-quality, uncompressed WAV songs.

    Thankfully, this problem has been diminished with the latest Bluetooth codecs.

    What is the Next Frontier in Bluetooth Headphone Technology?

    In the future, we can expect better lossy Bluetooth codecs that will deliver a near CD-like sound quality. Plus better power management system will prolong the battery life of Bluetooth devices.

    At the moment listening to music wirelessly takes away from the audio quality, which you can hear if you have a trained ear and the right equipment.

    Even though most people can’t detect the difference, test yourself here.

    Maybe, they’ll figure out how to make a lossless Bluetooth codec though these are just audiophile dreams at the moment.

    Best Bluetooth Headphones

    black Bluetooth headphones

    Check the related guides on top models you can get today.

    Sony WH-1000XM4 travel

    What are the best-rated Bluetooth over-ear headphones?

    Over-ear headphones with Bluetooth offer more convenience and excellent comfort. You can choose from many models from Sennheiser, Bose, V-MODA, and others. See best Bluetooth headphones.

    Sennheiser Momentum True Wireless 2 true wireless earbuds

    What are the best-rated Bluetooth earbuds?

    Smaller Bluetooth earbuds offer shorter battery life but unbeatable portability.

    Check the best Bluetooth earbuds.

    Jaybird Vista 2 on the ground

    What are the best-rated Bluetooth headphones for sport?

    Working out with wires is often annoying and creates accidents. There are many options from Jaybird, Bose, Jabra, Plantronics, and others. Free yourself from the cord and pick the best workout headphones.

    House of Marley Positive Vibration XL headphones

    What if I don’t want to spend more than $100?

    In that case, you can get some high-value-for-money wireless headphones that all cost less than 100 dollars.

    Check the best Bluetooth headphones under $100.