Wireless connectivity has revolutionized the way we listen to music, and it's incredible how accessible and affordable it has become. From true wireless earbuds to powerful Bluetooth speakers, we've come a long way since the days when wireless audio seemed like a futuristic dream. But there's more to this wireless world than meets the eye.
Bluetooth is the medium, but the codec is the secret sauce that determines the quality of your audio experience. In the early days, high-fidelity wireless audio was as elusive as the idea of wireless itself. Fast forward to today, and we have a range of codecs that promise audio quality that was once unimaginable.
However, not all headphones or earbuds are created equal when it comes to understanding these codecs. Similarly, your phone, laptop, or media player might not be able to transmit every codec. So, let's dive into the world of Bluetooth codecs and explore what they mean for your listening experience.
What's a Codec?
A codec, short for coder-decoder, is like a translator that encodes and decodes data. It's an essential part of our digital world, enabling us to talk on the phone, stream Netflix, or listen to Spotify. Think of it as the language that your devices speak to each other.
Bluetooth, for instance, is like a phone call between two people who might speak different languages. The codec is the language they choose to communicate. While this is a simplified analogy, it gives you a basic understanding of how codecs work within Bluetooth technology.
Conveniently, the codec 'language' is usually decided automatically once you connect your devices. Your phone and earbuds, for example, will agree on a common language to ensure seamless communication. In some cases, you can manually override this and force them to use a different codec, but we'll get to that later.
While the end result is the same - music in your ears - different codecs vary significantly in important ways. One crucial aspect is the bit rate, which determines how much data is transmitted per second. Imagine it as the size of the pipeline between your earbuds and your phone. A larger pipeline often means better audio quality, but it's not always the case. We'll explore this further.
It's important to note that these Bluetooth codecs are separate from the codecs used to encode the music itself. Even though some share similar names, these codecs are specifically designed for wireless audio transmission.
The Basics: SBC and LC3
The creators of Bluetooth understood the need for a common language, or 'lingua franca', to ensure all devices could communicate at a basic level. Without this, Bluetooth might not have become as popular and ubiquitous as it is today.
The common language for Bluetooth is SBC, or 'Low Complexity Subband Coding'. It was designed to provide decent sound quality while minimizing processing power to conserve battery life. All Bluetooth devices are required to support SBC. The sound quality can vary significantly depending on the manufacturer's implementation, but it can theoretically be quite good.
With Bluetooth 5.2, a new codec called LC3, or 'Low Complexity Communications Codec', became an option for manufacturers as part of LE Audio. LC3 promises higher audio quality at the same or even lower bit rates. Most mid-range and high-end Bluetooth earbuds and headphones now include additional codecs that offer similar benefits, often with a reputation for audiophile-grade sound.
Bluetooth Codecs Compared
Here's a comparison of some of the most common Bluetooth codecs:
| Codec | Sample Rates | Bit Depth | Bit Rate* | Typically Found In |
| ------ | ------------ | --------- | -------- | ------------------ |
| AAC | 44.1 kHz | 16 | 250 kbps | Apple devices, many headphones, Android devices |
| AptX | up to 48 kHz | 16 | 384 kbps | Android, many headphones |
| AptX HD | up to 48 kHz | 24 | 576 kbps | Some Android, headphones |
| AptX Lossless | Up to 96 kHz | 24 | Up to 1.2 Mbps | Some Android, headphones |
| AptX Adaptive | Up to 96 kHz | 24 | Up to 420 kbps | Android, newer headphones |
| LC3 | Up to 48 kHz | Up to 32 | Up to 245 kbps | BT 5.2 and newer devices |
| LDAC | Up to 96 kHz | 24 | 330/660/990 kbps | Sony devices, Android |
| SBC | up to 48 kHz | 16 | 345 kbps | All Bluetooth audio devices |
*Note: These are the highest potential bit rates, but actual rates may vary depending on the device. Bit rate alone is not a reliable indicator of audio quality. For example, AAC and SBC use psychoacoustic modeling, similar to MP3, which can make them sound better than their bit rate suggests.
The Next Step Up: AptX and AAC
Apple's preferred codec is AAC, or Advanced Audio Coding. Confusingly, this is also the name for Apple's alternative to MP3 for music files. In terms of Bluetooth, AAC is a more complex codec than SBC, which means it can potentially sound better at similar or even lower bit rates. This is why judging a codec solely based on its bit rate is misleading.
Historically, AAC has sounded better on iOS devices compared to Android due to differences in how they handle encoding. However, with most Android phones now supporting some form of AptX in addition to SBC, there's rarely a need to force AAC on an Android device. For Apple users, AAC is a solid choice, especially considering its low bit rate.
On the Android side, we have AptX, owned and developed by Qualcomm. In some ways, AptX is to Android phones what AAC is to Apple, but the specifics are more complex.
There are several versions of AptX, and both the source and the device need to support the same variant. However, it's often difficult or impossible to know which version is in use. While SBC's sound quality can vary depending on the manufacturer's configuration, Qualcomm sets a minimum performance level for AptX that's higher than SBC's lowest settings. In other words, SBC can sound worse than AptX, but it can also sound very similar.
Higher Fidelity (in Theory): LDAC and AptX Lossless
There are two semi-common codecs that promise even higher audio quality: LDAC and AptX Lossless. These codecs have significantly higher bit rates, but as we've discussed, bit rate alone doesn't guarantee better sound quality. The ultimate goal is lossless transmission, where the audio data from your phone reaches your ears without any loss in quality.
Sony's LDAC is their unique take on a Bluetooth codec. It's typically found in Sony headphones, but it's also available on a wide range of Android phones as the source. Like AptX Adaptive, LDAC has a variable bit rate (330, 660, or 990 kbps), making it suitable for less-than-ideal environments. However, it might default to one of its lower settings, in which case it's no better than other options. To ensure you get the highest quality, you'll need to adjust your phone's developer settings.
AptX Lossless has the potential for up to 1,200 kbps, pushing the limits of what's possible with Bluetooth audio. Qualcomm claims this allows for lossless transmission of CD-quality audio. However, like LDAC, it may drop to a lower bit rate if environmental or distance factors affect the data rate. In this case, it switches to a version of AptX Adaptive.
There are other, less common codecs, such as MQair, Samsung Seamless Codec, LHDC, and L2HC. Unless your phone or audio player and your headphones or speaker support one of these, there's no need to worry about them until they become more widely available. Manufacturers often create their own codecs to avoid licensing fees.
Does It Matter?
After all this, how much does the codec really matter? Here's a hot take: not as much as you might think. With a decent pair of headphones, a quiet listening environment, and a high-quality stream or download, you might be able to notice a difference between SBC at its worst and one of the better codecs at their best. However, this difference is subtle, and it's almost impossible to attribute it solely to the codec.
What truly impacts your sound quality is better headphones, a good fit, a quiet listening environment, and even improving the quality of the music stream itself. Services like Qobuz, Tidal, and Apple Music offer higher resolution than Spotify, but at least Spotify now has lossless audio. These aspects will improve your sound quality far more than changing the codec.
If you've optimized all these factors and want to squeeze out every bit of sound quality, it might be worth checking your phone's settings to see which codecs it supports. Sometimes, the phone or audio player defaults to a safe but poor-sounding option. Additionally, just because a codec is listed in the hardware specs doesn't mean it will work as intended.
Changing the codec on your phone or tablet won't magically transform $150 earbuds into $500 earbuds. However, it might enhance the sound quality you're getting or provide a more reliable connection when you're on the move.
When choosing between two headphones, it's better to go for the one with superior sound quality, even if it only supports AAC or AptX, rather than opting for one with LDAC or AptX Lossless but mediocre sound.
In addition to covering audio and display tech, Geoff also takes readers on virtual tours of fascinating locations around the world, from nuclear submarines to aircraft carriers, medieval castles, and more. He's the author of 'Budget Travel for Dummies' and a bestselling sci-fi novel about city-size submarines. You can follow his adventures on Instagram and YouTube.
