Bluetooth Explained: Why Your Headphones (Sometimes) Suck
Short-range tech, long-range impact
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I love Bluetooth. I use it everyday. I wear over-ear headphones for most part of my day and it was while wearing them that I got the idea to write an article on this amazing piece of technology. I thought some people would find the inner workings of Bluetooth as interesting as I would, so here it goes.
To many who don't know about the ins and outs, Bluetooth is purely magical, a technology that has changed life for tech consumers so much that it's pretty hard to think how people have lived before it.
In this article, I'll take you a bit deeper into the tech behind Bluetooth and we'll primarily explore the origins, applications and discuss the exciting future that Bluetooth has.
What Is Bluetooth?
To explain in a nutshell, Bluetooth is that invisible magic that helps your phones, laptops and other compatible devices to communicate with each other and other peripherals. If you have ever used a wireless device before, solid chances are it was using Bluetooth.
For a more realistic definition, Bluetooth is a short-range wireless communication protocol that is the de facto standard used by a range of wireless devices all the way from wireless mice, keyboards, speakers to wristbands and a lot more. Modern laptops, computers and phones widely support Bluetooth.
When two devices are connected via Bluetooth one acts as the host and the other as the listener. If I use an analogy, you can think of a guy with his radio tuning into an FM station. The station sends in the data and the radio effectively catches it. Bluetooth point-to-point communication happens in a similar way.
The Origins Of Bluetooth
Bluetooth was invented by a Dutch engineer Dr. Jaap Haartsen when he was working for Ericsson (A mobile company) back in the 90s. It was there that he found a clever way to use a specific type of radio signal to transmit data wirelessly.
Back in the late-90s when Bluetooth publicly released, it wasn’t an upstart star that everyone started implementing right away. Mind you, even USB wasn't as widely adopted at that time. There was still a mess of many different cables to transmit data among computers so wireless communication was largely a lab thing.
In my previous article, I briefly discussed the mess of different USB connectors that existed around the same time Bluetooth debuted, If you’re interested, I have linked it down below for you:
Bluetooth was made for mobiles and naturally the power element was a major concern. It was made for low-power devices. It uses the same 2.4 Ghz frequency as your WiFi router but it doesn't interfere with it because of frequency hopping techniques.
Fun Fact: 'Bluetooth' is named after a Viking King who literally had a blue tooth. The Bluetooth logo itself bears the initials of that king.
What Goes Behind A Bluetooth connection
Bluetooth Classic has a simpler working mechanism where two compatible devices when in-range automatically do the authentication and get ready for data transfer. But in Bluetooth LE, it's different. We'll discuss Bluetooth versions in more detail in the next section.
Bluetooth LE works differently than the classic version because a Bluetooth LE connection goes over a couple of steps which are detailed down below:
Scanning
When you want to connect to a Bluetooth device, you enable scanning mode on one of the devices which triggers it to act as a host device. The host sends discovery packets to other available Bluetooth devices in the vicinity.
The discovery packets sent by the host device include information about the kind of device it is and what sort of device the host is looking to connect to. This information can include physical address, human readable name and much more. In this phase, the host is effectively saying out on the street: "Hey! Anybody wanna talk?".
Once an active device is found, both share information about the type of device they are and we move to the next step - Pairing.
Pairing
Pairing is when both the host and the listener device has enough information about each other and the connection that is going to be established between them. Now they need to pass in some essential information to 'trust' each other before a connection is established.
Think of two people meeting in the street. Once the devices are sure of each other they initiate a 'handshake' which is an exchange of information which includes a key that encrypts their communication. This key holds the channel hopping that would take place between the Bluetooth devices.
For security reasons bluetooth hops between different channels about 1600 times a second (Crazy!, right?) so even if someone is tapping into the frequency they effectively couldn’t get a hold of the actual data that is being shared among the devices.
Sometimes we can see a PIN confirmation, that is just an additional security measure used just to confirm that the device you want to connect to indeed is the one you are connecting to. After successful pairing both of the devices head to the last stage - Connection.
Connecting
After pairing, once a successful connection is established the subsequent communication packets include that data that will be communicated between the two devices.
If no data is being transmitted, the listener device goes into sleep mode and is woken up by the host device which resumes data transfer between the devices. An example would be a paused music playback between a phone and a pair of wireless earbuds.
The Different Versions of Bluetooth
Let's first answer the question: "Do Bluetooth versions matter for you?"
The answer is a bit more nuanced but yes, they do matter. As a matter of fact, Bluetooth versions are what entail what speed, battery-life, range and features your compatible devices would have. One really good thing is that newer versions are backwards-compatible with older Bluetooth versions.
Now, there are various versions of Bluetooth, they get released every now and then but I won't bore you with all of the versions. I'll talk about 3 of the most important Bluetooth versions down below:
Bluetooth 4.0
Bluetooth 4.0 popularly known as Bluetooth Low Energy was released back in 2010. As the name suggests, the major innovation here was that these versions used really low-energy. So low that many Bluetooth LE devices could be run for months on a coin cell battery.
Bluetooth LE meant that your fitness bands could last a week on a single charge. Devices like smart-locks and fitness bands made wide use of Bluetooth 4.0.
Bluetooth 5.0
Bluetooth 5.0 was a significant improvement over the Bluetooth LE. While it didn't include a plethora of exciting features it radically improved upon the speed and range of Bluetooth LE.
For the paper specs, here's how Bluetooth 5.0 improves on the previous Bluetooth LE:
2x Data Transfer speed
4x Range (Operating Range)
8x Broadcast Space (The Scanning range)
The ability to connect multiple wireless devices also debuted with Bluetooth 5.0 In a nutshell, Bluetooth 5.0 was a serious improvement over the Bluetooth LE in terms of raw performance that doubled and quadrupled over a generation.
Bluetooth 6.0
Released back in 2024, Bluetooth 6.0 is a precise improvement to the prior versions. The main features with this iteration of Bluetooth was channel sounding which basically is that two Bluetooth 6 devices can tell how close they are placed up with quiet accuracy.
Instead of just guessing on signal strength, Channel sounding means that you can locate your devices up pretty accurately. The distance can also be plotted over a radar inside a mobile app.
Here’s a 3 line summary for the Bluetooth versions we discussed:
Bluetooth 4.0 - Vastly improved Bluetooth’s power efficiency, released back in 2010
Bluetooth 5.0 - Double the speed, Quadruple the range, released in 2016
Bluetooth 6.0 - Precision-based tracking features, Auracast, released in 2024
Why Bluetooth Sometimes Stutters?
While there can be many reasons for Bluetooth stutters, most come down to Physics. When you have reflecting environments like metal elevators or a lot of noise around the operating frequency of your device you're bound to experience glitches.
WiFi, Baby monitors, operate at the same frequency as Bluetooth. A lot of Bluetooth devices operating in the same area can cause stuttering or connection losses. Microwaves are notorious to break up wireless signals too for devices operating on this range.
Low Battery is also one of the reasons for poor quality Bluetooth communication. A low battery can directly impact the signal strength affecting the quality of the end application both for the transmitter and the listener.
While no country is short of knock-off products, Pakistan is filled with 2,000k pkr knock-offs that don't have good quality components. These products would feature weak components like the antenna or transmitters that result in an overall poor Bluetooth experience.
Custom Bluetooth Improvements by Manufacturers
Back in 2016, Apple introduced its First Generation Airpods and it made use of a custom processor called W1. This was a proprietary chip inside the Airpods that sits between the Bluetooth radio and Operating System facilitating Bluetooth operations.
Apple's custom chip helped abstract away the pairing process, antenna tuning and adjusting power levels. The chip helped in pairing by tying the Airpods's Bluetooth key with the iCloud account.
In 2022, Apple shifted to the newer H2 chip replacing the previous H1 chip that succeeded the W1. The newer H2 chip further helped in noise cancellation and better frequency hoping to avoid congested channels. It also supported Automatic Device Switching.
In 2017, Google also worked on Fast Switch for Android. Samsung also offers a similar feature.
The Exciting Future Ahead
Bluetooth is one of the really exciting technologies that don't get much attention. It truly is revolutionary. The 20+ years old technology has impacted computers especially portable devices like few and it still continues to improve as time passes by.
With time Bluetooth has continued to evolve with new features, greater performance and much more optimized battery life - all while being backwards compatible with the previous Bluetooth versions.
Auracast
One of the highlights of Bluetooth 5.2 was Auracast. Traditionally Bluetooth was capable of point-to-point communication but through Auracast one can act as a broadcast station and transmit to multiple devices at once.
Basically, you set up a mini FM station on a phone or a laptop and use that to connect to a virtually unlimited number of devices that can tune into the media all at once while being in-sync.
Opera houses can have their QR codes or NFC tags to scan for listeners to tune into the Bluetooth broadcast using Auracast. This is similar to how we join public WiFi through scanning QR codes.
Since Auracast is a recent feature that supports newer versions of Bluetooth it will take some time before we see it become more prevalent among the larger population.
Centimeter-level Location
Channel Sounding is the precise tracking feature that allows newer Bluetooth devices to pin-point their location along with the direction to move towards to find them.
For a more practical application, Channel Sounding is good enough to tell under which sofa resides the TV remote. Moreover it can help block a car unlock unless your phone is near the car.
Channel Sounding that came with the newer versions of Bluetooth would virtually add 'Find My' to every device that supports the required Bluetooth version. With the improved range and precise location it could add some pretty nice quality-of-life improvements.
My Thoughts
Even if you’re someone who isn’t excited about features like Channel Sounding or Centimeter-level Location being more common across Bluetooth supported devices, you can still appreciate the convenience and comfort that Bluetooth brings, at least I do.
I used to primarily drive wired over-ear headphones with my laptop. I move around between the library and my home with my laptop and turning to Bluetooth headphones has made such an improvement to my workflow that I never want to go back.
Wires have their place but once you’re used to the convenience that Bluetooth brings, I think it’s hard to go back at least this has been in my experience and I’m sure I’m not the only one.
Nice article mate !!!!