Many of us use Bluetooth every day, but few truly understand what it is and the intricacies of how it works. In this article, we'll break down Bluetooth – what it is, why we use it, a brief history, how it works – and the different versions that have shaped its evolution. Most importantly, we'll highlight which versions you should look out for when shopping for the best speakers, headphones, and smartwatches.
What is Bluetooth?
Bluetooth is a short-range wireless technology that exchanges information across devices over short distances. It lets you connect your smartphone to your speaker, your headphones to your smartwatch, your laptop to your TV – all without needing a single wire.
Why do we use it?
Bluetooth makes our lives easier by enabling hands-free calling, wireless audio streaming, and seamless device synchronisation, among other benefits.
An example I use regularly is the CarPlay feature introduced with Apple's iOS 17 update in September 2023. Building on iOS 15's SharePlay, CarPlay allows users to play music together in the car. Start a SharePlay session, and passengers can add songs to the journey's playlist, contributing to the music without the chaos of cables or faff of phone sharing.
A brief history
In the 1990s, Ericsson, Nokia, and Intel developed wireless technologies for mobile phones and laptops, eventually joining forces and creating Bluetooth, a standard for short-range wireless communication. Initially overseen by the IEEE, the Bluetooth Special Interest Group (SIG) now manages the standard with over 35,000 companies. This widespread adoption is why Bluetooth is present in nearly all the devices we use today.
Interestingly, "Bluetooth" comes from Danish King Harald "Bluetooth" Gormsson, known for uniting Denmark and Norway and having a dead, bluish tooth. When Intel, Ericsson, and Nokia standardised the technology, the name "Bluetooth" was suggested as a temporary codename and eventually stuck. Meanwhile, the logo was created by combining runes representing Harald's initials.
How Bluetooth works
Basic principles
Bluetooth transfers information over short distances using radio waves in the 2.4 GHz ISM band. Unlike Wi-Fi, which can cover larger areas, Bluetooth prioritises using less power to save battery and avoid signal interference.
Pairing and connectivity
Bluetooth devices must first be paired in order to connect. Once this process is complete, devices can remember each other, allowing for quicker connections in the future.
Range and speed
The typical Bluetooth range is about 33 feet (10 metres), with a transmission power of around 2.5 milliwatts. This low power consumption is why small devices like wireless earbuds can operate without quickly draining their batteries. The speed of data transfer depends on your device's Bluetooth version.
The evolution of Bluetooth
Since its introduction in 1999, Bluetooth technology has gradually evolved, offering faster data transfer, further range, and improved features. From 1.0 to 4.2, early versions laid the groundwork, while key developments like Enhanced Data Rate (EDR) in Bluetooth 2.0 and Low Energy (LE) mode in Bluetooth 4.0 were pivotal later on for IoT (Internet of Things) devices.
Bluetooth 5.0 and beyond
Bluetooth 5.0, released in 2016, marked a huge advancement with a range of up to 240 metres. Later versions have built on this:
• Bluetooth 5.1 (2019): Direction-finding for better location accuracy.
• Bluetooth 5.2 (2020): LE Audio for better synchronisation for streaming.
• Bluetooth 5.3 (2021): Improved efficiency, security, and power management.
• Bluetooth 5.4 (2023): Additional enhancements with added aptX Lossless support.
What's the best Bluetooth version?
Short Answer: We recommend Bluetooth 5.0 and above. However, for things like DAB radios, anything above and around Bluetooth 4.0 is fine.
There isn't a hard and fast rule for choosing the best Bluetooth version, as what you choose will largely depend on your budget, experience level, and how often you intend to use the product. For instance, a portable radio or bookshelf speaker with Bluetooth 4.0 is perfectly fine. Meanwhile, for something like an iPhone, you'll want a device that, for security reasons, offers the latest version.
In general though, aim for Bluetooth 5.0 or higher. Released in 2016, Bluetooth 5.0 introduced significant security improvements – LE Privacy, improved EDR and MAC address rotation – and an increased transmission range of up to 200 metres. Earlier versions are more susceptible to cyber-attacks such as 'bluebugging' (where hackers gain access to a device via a discoverable Bluetooth connection) and 'bluesnarfing' (theft of information from a Bluetooth-enabled device). This is why having up-to-date Bluetooth on your smartphone or laptop, where sensitive data such as passwords are stored, is so important.
How to stay safe with Bluetooth
When you pair your device, such as connecting a phone to a speaker, data sharing begins after making the connection. This pairing process in itself adds a layer of security. However, like Wi-Fi connections, Bluetooth connections – voluntary or not – can still expose personal data if you're not careful.
Frequency Hopping: When transferring data, a large part of Bluetooth's security comes from "frequency hopping". This is when a device quickly changes its transmitter frequency to prevent interference, monitoring, and attacks. By hopping up to 1600 times per second across 79 channels, Bluetooth makes it extremely difficult for hackers to intercept data. For the most part, the newer the Bluetooth version, the faster and safer this "hopping" becomes.
Security Tips
• Turn off Bluetooth when not in use: Leaving Bluetooth active can expose your device to attackers.
• Be cautious with rental cars: Unpair your phone and clear data from the vehicle before returning it.
• Use Hidden Mode: Always use Bluetooth in hidden rather than discoverable mode if available.
Final thoughts
In today's tech-driven world, Bluetooth is the invisible thread connecting most, if not all, of our devices. Of the seemingly endless number of Bluetooth versions, we recommend you aim for Bluetooth 5.0 or higher when shopping online to ensure your device offers the best performance, privacy and protection against your data.
Harvey Isitt is a Tech Writer and Reviewer for What's the Best. Harvey writes reviews, buyers and how-to guides, and listicles on a broad range of topics.
Besides writing, Harvey is an avid camera, turntable, and speaker enthusiast with a somewhat unhealthy obsession with movies. He is also a keen runner, cyclist, hiker, and swimmer.
Subscribe to the What's The Best Newsletter to keep up to date with more of the latest reviews and recommendations from the What's The Best team.