What is the Best Bluetooth Audio Codec for Headphones?
The Bluetooth wireless standard has revolutionized the world of headphones. Nowadays, wires are most often found in high-quality headphones or in simpler ones, like those that come with new smartphones in their boxes. However, to listen to music using technology, data packets need to be compressed on the cell phone to be decompressed later on the headphones.
Audio glossary for this article
Term | Application | Explanation |
---|---|---|
Sampling depth | The codec supports sampling depths of up to 24-bit. | The “resolution” of the sound data that is stored in files. The more, the merrier! |
Sampling rate | The sampling rate is 48 kilohertz (48,000 hertz, i.e. 48,000 times per second). | The frequency at which an analog signal is transmitted. |
Data Rate | The codec reaches 345 kilobits per second. | The amount of data transmitted per second. |
Latency | Latency is 200 milliseconds. | The delay (lag) that occurs between the transmission and output of the signal. |
And this is exactly the point where opinions on current Bluetooth headphones differ. Depending on the audio codec used, this compression and decompression may make no difference or result in a considerable loss of quality. So, to help you estimate how much of this connection will be loss-free when purchasing a new headset, we explain more about the most important Bluetooth codecs used in the current market.
As Bluetooth transmission standards are complex and I want to make this article easy to understand for as many readers as possible, I will focus on the most important advantages and disadvantages. You can feel free to discuss the details about each of them in the comments box at the end of the text!
SBC
The SBC audio codec stands for “Low Complexity Subband Codec”, or “low complexity subband codec”, in literal translation, and can be classified as the most basic. It is usually found on cheap headphones because it can be used without a license, and is part of the Advanced Audio Distribution Profile (A2DP). Even though SBC is widely used, its compression results in very noticeable losses in audio quality.
For wireless connections, SBC maxes out at 320 kilobits per second at 48 kilohertz. Therefore, the codec is not suitable for playing music. Another disadvantage is that the sound quality can drop more easily. In other words, if a headset only provides the SBC format, the audio quality will not be the best.
AptX (HD)
If you see the AptX logo, or even AptX HD, on the packaging of a headset, you can rest assured. This audio codec was developed by Qualcomm and means “Audio Processing Technology”, or “audio processing technology” in free translation. Its main characteristics are higher bitrates and, mainly, lower latency.
In the HD version, AptX supports up to 24 bits of resolution, and the maximum rate is 567 kilobits per second at 48 kilohertz sampling. AptX without HD offers a maximum of 386 kilobits per second at 48 kilohertz, and a sampling depth of 16 bits.
Even though the latency of AptX HD and AptX is between 170 and 270 milliseconds, Qualcomm still has a secret up its sleeve: the low latency AptX LL. So, it achieves low latencies of up to 40 milliseconds, which is an advantage in headphones used for gaming or playing musical instruments.
Regarding smartphones, a big problem with AptX is that Apple no longer supports this codec. Therefore, if you connect AptX HD headphones to an iPhone, you will not notice any advantage. However, since AptX is backwards compatible with SBC, it can still be used in this case.
AptX Lossless
Announced by Qualcomm in September 2021, the AptX Lossless codec arrived with the promise of lossless audio streams with standard CD quality. Although it is not the same as Hi-Fi/Hi Res formats, as it offers 44.1 Khz at 16 bits, the manufacturer highlights the new format as ideal for streaming services with premium audio quality.
When we talk about codecs, a very common problem is that AptX Lossless requires support on both the smartphone and the headset, and there is no expectation of compatibility with the iPhone family.
AptX Low Latency
AptX Low Latency is another upgrade to Qualcomm's base AptX standard. As the name suggests, the codec prioritizes low-latency audio reproduction, with a delay of approximately 40 ms. The extension is ideal for professional players or even to solve problems with audio out of sync with the image.
AptX Adaptive
With AptX Adaptive, Qualcomm introduces us to a successor to AptX. The codec is flexible and can switch between the advantages of the various existing AptX standards, while also offering a low latency mode suitable primarily for gaming and watching movies on mobile.
In cases where low latency isn't important, AptX Adaptive is great because it achieves very high bitrates, from 279 kilobits to 420 kilobits per second. According to Qualcomm, latency is specified at just 80 milliseconds. Additionally, the codec is backwards compatible with AptX and AptX HD. So even if your device supports Adaptive but your headphones only support HD, AptX HD can still be enjoyed.
LDAC
If you want to reduce losses less when playing music on your wireless headphones, you should pay attention to the LDAC codec. Developed by Sony, it can be found in the most current headphones, such as the Sony WF-1000XM4 or WH-100XM4. The codec delivers a maximum of 990 kilobits per second, with a sampling depth of up to 32 bits at 96 kilohertz.
As LDAC is part of the Android open source project, AOSP (Android Open Source Project), since version 8.0, several devices have become compatible with the standard. If this is the case with your headset, you can find the HD quality option via LDAC in your phone's Bluetooth settings. However, as the default bitrate for devices is not specified, in this case you must access Android settings to make adjustments on your device.
As we mentioned before, if you use an Apple device you won't benefit from LDAC-compatible headphones. But we will address the case again later in this article.
LHDC
The LHDC codec is another standard that relies on high bit rates. In theory, it has been ready since Android 10 to be used by software developers and integrated into system interfaces. However, in practice, support for LHDC is not yet widespread. See the following example:
The OnePlus Buds Pro supports the LHDC standard and, combining the buds with the OnePlus 9 and OnePlus 9 Pro smartphones, offers the best sound quality compared to other Android phones. But even if the main line has compatibility, OnePlus does not extend support to its entire product line. Therefore, cheaper models, such as the OnePlus Nord 2, do not have the technology.
The LHDC standard, however, has not become as popular despite its impressive features, featuring bit rates of up to 900 kilobits per second, in 24-bit definition and sampling rates of 96 kilohertz. This did not happen even with the codec's partnership with some manufacturers, including premium audio brands such as Sennheiser, Audio-Technica and Edifier, or chip and smartphone manufacturers Cirrus Logic and Huawei, respectively.
AAC
The AAC (Advanced Audio Codec) audio codec is standard on iPhones and iPads, but is also compatible with Android devices and notebooks. Although the technical characteristics of the standard, which presents 96 kilohertz and 320 kilobits per second at 24 bits, do not seem that impressive, the quality of AAC is quite interesting.
This is because AAC file transfer is based on psychoacoustic models, which when compressing consider the sounds that human ears are capable of detecting. As this requires greater processing power and power management works differently on Android and iOS, the codec offers better sound quality on the iPhone.
How does the website Soundguys explains, AAC-compatible headphones are clearly recommended for iOS device users. And since quality on Android depends on many factors, just pay more attention to the previous codecs if you don't have or don't intend to buy an iPhone.
LC3
Since Bluetooth 5.2, a new audio codec has been released: LC3. The standard, however, is still niche, but I include it in this article because it is basically the successor to the SBC. As the website Bluetooth.com illustrated in a video, the LC3 is capable of maintaining high audio quality with a low sampling rate.
The LC3 codec is not yet widespread, but it is a very interesting promise for “geeks” or audio enthusiasts.
LE Bluetooth Audio
LC3 is part of the Bluetooth LE audio specifications, which were announced in 2020. At the time, the original audio features were also retroactively renamed to “Classic Audio.” In addition to the new codec, Bluetooth LE incorporates new features, here are some of them:
- Multi-Stream Audio (MSA) – For varied audio streams synchronized between source and playback device;
- Hearing aid support – Better support and standardization;
- Auracast Broadcast Audio – An option for use in public spaces, offering an audio stream that can be heard by multiple people.
Now that we've covered the most important codecs, let's talk about the following question: what is the best audio codec?
Conclusion: Is there a “best” audio codec?
In the world of technology, there is an arduous battle for the “best”, with the most complex relationships being divided and compared based on numbers. However, just as a 108MP camera doesn't result in better photos than those taken with a 12MP sensor, the same goes for Bluetooth codecs.
If you want to listen to a premium streaming platform with as little loss as possible, LDAC could be a good option. However, with it, you will only enjoy its benefits if you have an Android device, and even then you may have to make some changes to the settings. AptX HD has a good balance between distribution and compression, but again users of Apple products are left out.
In short, before discarding a headset because it doesn't support a certain audio codec, try testing it in practice or even reading the reviews of those who have already tested it, as you can do here at Nextpit. Looking for better sound quality always means having a more holistic view. And that's where audio codecs play an important role in demand, but not the only one.
Article updated in October 2024 with new codecs and a list of features for Bluetooth LE Audio.