- Bluetooth is a short-range wireless link that uses the same 2.4 GHz band as many Wi-Fi devices.
- Most problems are solved by turning Bluetooth off and on, forgetting the device and pairing again.
- Newer Bluetooth versions improve range and efficiency, but your phone and headphones must both support them.
The short answer
Bluetooth is a way for two nearby devices to talk to each other without a cable. It connects phones to headphones, speakers, cars, watches, keyboards and many other gadgets. The name comes from Harald “Bluetooth” Gormsson, a Danish king who united tribes, which is a fitting image for a technology designed to unite devices.
How Bluetooth works
Bluetooth devices send radio signals in the 2.4 GHz band, the same busy band used by many Wi-Fi routers, microwave ovens and other gadgets. To avoid clashes, the signal quickly hops between many channels. Before two devices exchange data, they pair: they identify each other, confirm they are allowed to connect and create a shared key to protect the link. After pairing, they remember each other and reconnect automatically when they are near.
Typical range for headphones and phones is about 10 metres in open space. Walls, your body and other devices reduce that distance.
What the versions mean
| Version | What it improved |
|---|---|
| Bluetooth 4.x | Introduced low-energy mode, which made fitness bands and tags possible. |
| Bluetooth 5.x | Better range, speed and efficiency, plus support for more devices and features. |
| LE Audio | A newer audio system that supports better quality at lower power and features like sharing audio with several listeners. |
A newer version only helps when both devices support it. Pairing a new pair of earbuds with an old phone gives you the older phone’s features.
Audio quality and codecs
A codec is the method used to squeeze sound into the Bluetooth link. The codec both devices share decides the quality and delay.
- SBC: the basic codec every device supports. Fine for casual listening.
- AAC: common on iPhones and works well for music.
- aptX and LDAC: found on many Android devices and some headphones, offering higher quality when both sides support them.
For recording, mixing or video editing, wired headphones are still better, because Bluetooth always adds a small delay.
Fixing common problems
- Restart Bluetooth. Switch it off and on again on the phone.
- Check the battery. Low charge on either device causes drops and failed pairing.
- Forget and re-pair. Remove the device in Bluetooth settings, put the accessory in pairing mode and connect again.
- Move closer and remove obstacles. Keep the phone on the same side of your body as the earbuds.
- Reduce interference. Turn off nearby devices that you do not need, or move away from a crowded Wi-Fi router.
- Update software. Install updates for the phone and for the accessory’s own app.
- Reset the accessory. Most headphones have a reset method in the manual, which clears old pairings.
Sound cutting out or lagging
If audio stutters, the cause is often distance, interference or a phone that is busy. A video that looks out of sync may be a codec delay; many video apps correct this, but not all. If lag is a problem in games, choose headphones marked as low-latency or use a cable.
Staying safe with Bluetooth
- Turn Bluetooth off in public places when you are not using it.
- Do not accept pairing requests you did not start.
- Keep device software updated, because updates fix security problems.
- Rename your devices so you can recognise them in a crowded place.
Quick checklist
- Charge both devices before pairing
- Forget and re-pair when connection fails
- Keep devices close and clear of obstacles
- Use wired headphones for audio work
- Update your phone and accessories
Key points to remember
Bluetooth is convenient and mostly trouble free, and when it fails a simple reset usually fixes it. If your phone also feels slow or its battery drains quickly, see our guides to speed up a slow laptop and to phone care.
