Up until just over a decade ago, we were all walking around with wires stuffed into our pockets, listening to our favorite tunes on our iPods. There were few things as frustrating as having to sit and untangle your earphones when you got home. Today, things have changed and wireless earbuds are the new standard. But how do these wireless earbuds work?
Types of Wireless Earbud Connections
Bluetooth is the standard wireless protocol for wireless earbuds, it’s affordable, effective, and supported by a broad range of products without needing additional attachments such as receivers and transmitters. However, RF (Radio Frequency) earbuds are still offered as a less common low-latency alternative, primarily used in wireless speakers for TVs, many of which have an earbud-style design. Here’s how these wireless technologies are used to deliver sound from your device to your ear.
Bluetooth Connectivity
Wireless earbuds use Bluetooth connectivity to transfer audio from supporting devices. Both the earbud and the source device (phone, tablet, etc) must support Bluetooth as the source device sends the Bluetooth signal using a Bluetooth transmitter while the earbuds receive the signal using a built-in Bluetooth receiver.
How It Works
This pairing creates a two-way connection that allows the earbuds to receive audio data, while also facilitating the sending of audio data from the earbud to your phone. This is essential for earbuds with built-in microphones.
When you connect your wireless earbuds to your phone, a connection is established using a frequency band of 2.4 GHz. Once a paired connection is established you’ll need to remain within range of your device to ensure a stable connection without drops. Range varies slightly between each device and the Bluetooth versions being used.
Typically, one of the two earbuds will be a master earbud that receives the audio from the device and then sends it to the secondary (slave) earbud.
Compression
Compression is a key feature of Bluetooth, the efficiency of the compression determines both the retention of sound quality and the latency experienced. This has been a core focus of Bluetooth development in recent years, and several new Bluetooth codecs have facilitated low-latency connections that are better suited for watching videos and gaming than older Bluetooth codecs, which would frequently suffer from sync issues.
Digital audio is just like any other data, comprising binary, and effective compression can reduce the file size, allowing it to be transmitted from the device to the earbud quicker than a larger file. It’s a little more complicated than just reducing the file size though, as it needs to retain its integrity while being compressed. Some older Bluetooth codecs were effective at compression, but not at quality retention.
Over the last five years, there have been marked improvements in Bluetooth compression. LDAC, aptX HD, and aptX Adaptive are all examples of codecs that focus on retaining audio quality while also effectively reducing the size.
For gaming and watching videos, where latency is the most important quality, aptX Low Latency, LHDC, and LLAC are all excellent.
Bluetooth Codecs
I’ve included a summary of the most common Bluetooth codecs and a small bit of information on what they’re best known for.
SBC (Subband Coding) – The default codec for Bluetooth audio. It provides a balance between sound quality and compression but tends to have higher latency.
AAC (Advanced Audio Codec) – Offer improved audio quality over SBC. It’s commonly used in Apple devices.
aptX – Developed for increased latency performance over AAC and SBC, supporting higher-quality audio.
aptX HD – Enhances aptX with support for 24-bit high-definition audio, providing listeners with better sound quality.
aptX Adaptive – Adapts audio quality and latency dynamically based on the connection quality, balancing performance and reliability.
LDAC (Low Latency Audio Codec) – Developed by Sony, LDAC supports high-resolution audio streaming and offers three different bit rates for varying audio quality.
LC3 (Low Complexity Communication Codec) – LC3 is the new standard codec in Bluetooth 5.2 and is designed to provide high audio quality with lower power consumption and improved efficiency.
Limitations
Despite its plethora of benefits and dominance in wireless connectivity, Bluetooth isn’t without its shortfalls. By its nature, Bluetooth is prone to range limitations, and moving too far from the source device can cause jittery connections or even cause the connection to drop. This means it’s important to stay close to your device while using them.
Bluetooth is also not as strong as modern Wi-Fi, meaning it can’t penetrate through walls the same way. Even at a relatively short distance, Bluetooth connections can suffer without a direct line of sight between the earbuds and the device.
Radio Frequency Earbuds
Even though Bluetooth is a form of radio frequency, it is also slightly different from RF technology found in earbuds intended for watching TV and for the hearing impaired. Unlike traditional Bluetooth which operates in the 2.4 GHz band, it has a broader range of frequencies and doesn’t rely on such comprehensive compression methods. RF is a more direct communication.
RF earbuds are almost always specialty designs and you won’t find them advertised for casual music listening. Instead, their low-latency performance makes them a viable option for those looking to minimize syncing issues between the visuals and audio of their TV.

How Earbuds Produce Sound
Earbuds work similarly to headphones and other traditional speakers, just scaled down into a compact size. The process is relatively simple and is true for the majority of earbuds on the market.
Step 1. Audio Source (Phone/Tablet/Computer)
The audio data is generated by the source device.
Step 2. Compression
The audio data is compressed using Bluetooth codecs (such as SBC, aptX, and AAC) to reduce file size.
Step 3. Transmission
The compressed audio data is sent wirelessly using Bluetooth protocols. The Bluetooth transmitter in the source device sends the data on a 2.4 GHz frequency band.
Step 4. Reception
The earbud’s built-in Bluetooth receiver picks up the transmitted audio data. The master earbud (in a pair) receives the signal first and may send it to the secondary (slave) earbud if necessary.
Step 5. Decompression
The received audio data is decompressed to its original format. This step ensures the audio quality is as close as possible to the source.
Step 6. Digital Signal Processing (DSP)
The decompressed audio data is processed by the earbud’s internal DSP (Digital Signal Processor), which can further enhance the audio.
Step 7. Digital-to-Analog Conversion (DAC)
The processed digital audio signal is converted to an analog signal to be playable by the earbud driver.
Step 8. Driver Activation
The analog signal is sent to the earbud’s driver (miniature speaker) which vibrates according to the analog signal.
Step 9. Sound Production
The vibrations create sound waves that travel through the air. These sound waves enter your ear canal, hitting the eardrum and allowing you to hear the audio.
Built-in Batteries
Built-in batteries are central to any wireless design and modern earbuds typically have two different types of batteries to consider. There is a battery built-in to each earbud that provides around 2 to 6 hours of playtime (depending on the model), and then there’s the charging station (also called a charging case) which can typically charge the earbuds several times before needing recharging.
To charge earbuds with a charging station, simply place the earbuds into their charging station and ensure the connection points line up between the station and the earbuds. Most charging stations nowadays have a built-in magnet to help pull the earbud into its correct charging position.
It’s essential to understand that battery consumption varies between the types of features, functions, and volume levels that you’re using. Features like ANC for example, can increase battery consumption.
Noise Cancelling
Active noise cancellation earbuds are a relatively new addition to the market that reduces environmental noise, improving perceived audio quality and removing distractions. This technology is ideal for office workers or those who frequently commute on public transport.
Noise-canceling is achieved by using a variable amount of built-in microphones that gather information about the noise around the user, dynamically invert those frequencies, and play them back to the user. The result of the inverted frequency being played is that it cancels out the surrounding noise.
For a more detailed dive into how ANC works, I recommend reading our comprehensive guide on the different types of noise canceling used by wireless earbuds.
Conclusion
Wireless earbuds have become extremely popular, offering a clutter-free solution to private audio. They can be used with any device that supports Bluetooth transmission and offer a discreet and effective way of listening to music or watching videos while on your phone.