Now that headphone jacks are a thing of the past, Bluetooth audio devices have taken over to provide users with the most optimal listening experience. And with the rise in popularity of Bluetooth headphones and speakers, it’s important for people to have a basic understanding of Bluetooth 5.0 codecs and other Bluetooth formats.
Compared to the previous generation of Bluetooth, namely 4.2, Bluetooth 5.0 raises the bar by increasing the range of connectivity and providing faster data transfer speeds. Hence, improving overall audio quality. Another important feature that is often overlooked about Bluetooth technology is that it is backward compatible. That means if your phone supports Bluetooth 5.0 and you are using a Bluetooth 4.2 speaker, they will be able to connect with each other and work just fine.
The benefits of Bluetooth 5.0 cannot be understated. First of all, the evolution of Bluetooth Low Energy has come a long way. This is a feature of Bluetooth 5.0 that allows your device to run longer on a single charge as the amount of battery drained when Bluetooth is on has been significantly reduced. Next, the range of Bluetooth 5.0 has been increased to cover up to 240 meters. So, users can reliably use Bluetooth devices without having to worry about the connection becoming weak if they walk a few meters away. Last but not least, Bluetooth 5.0 allows users to connect two devices simultaneously, which means people are no longer limited to using a single device as their audio source.
So, in order to learn more about Bluetooth 5.0, we need to first familiarize ourselves with some basic knowledge and commonly used terms. Let’s dive in!
What Is Bluetooth?
Bluetooth is a short-range wireless technology that is used to exchange data between devices within a personal network. This technology is commonly used to transfer files and play audio wirelessly.
But have you ever wondered how your phone is able to play high-quality music from a Bluetooth device without ever buffering? This is done by encoding and decoding audio files.
What Are Encoding And Decoding?
Since audio files can vary in size as per the quality of the sound, it is necessary that the file is compressed using an algorithm. This process is known as encoding. Otherwise, if the file is much larger than the bandwidth of the Bluetooth connection, then your audio will start to stutter. So, when the compressed file is received, it is then decoded into a viable audio file, which can then be played. The technology used to compress and decompress these files is known as a codec.
What Is Audio Compression And What Are The Different Types?
As we are on the topic of audio compression, let’s discuss it further. There are three types of audio compression: uncompressed, compressed lossless, and compressed lossy. Here is how they compare against one another.
|Compressed lossless||Has good compression ratio and negligible processing time while retaining all data.||Files are comparatively larger than compressed lossy files.||FLAC, ALAC|
|Compressed lossy||Most popular audio file format while also being very small in size.||Certain parts of the audio are removed using psychoacoustic models.||MP3, AAC, ATRAC, WMA|
|Uncompressed||No data is removed and has great compatibility, even with older software.||Massive file sizes.||WAV, AIFF, BWF, LCPM|
Common Audio Terms
- Sample rate (Hz): Sample rate or sampling rate is the number of samples taken per second from an uninterrupted signal to make a digital signal. It is measured in hertz (Hz) and is most commonly found as kilohertz (kHz). High-resolution formats typically have a sample rate of 96kHz or higher. However, a higher sample rate also means that the file size would be larger as well.
- Bit depth (-bit): Bit depth is the number of bits of information in each sample. In simpler terms, a higher bit depth is able to record a signal more accurately. For instance, high-resolution formats usually have a bit depth of around 24-bit. And similar to sample rates, the higher the bit depth, the larger the file.
- Bit rate (kbps/Mbps): Bit rate is the amount of data that is being transferred from one Bluetooth device to another per second. It is calculated by multiplying the sample rate with bit depth.
- Data rate: It refers to the amount of data that is being transmitted each second.
- Sampling depth: Sampling depth determines the resolution and quality of an audio file. Think of how videos have different resolutions, i.e. 720p, 1080p, 4K, etc., sound also has a resolution.
- Latency (ms): It is the delay that occurs when a signal is transmitted and when the signal is outputted. Latency is measured in milliseconds. Since we are talking about delays in audio, it is preferred to keep latency as low as possible.
- Psychoacoustics: This is a very common term thrown around by audiophiles. It refers to how human beings perceive sounds. However, in the case of digital media, psychoacoustic models are applied to determine what part of an audio file can be removed to reduce the file size without causing any noticeable loss in sound quality.
All of these terms are important to know because you are likely to hear them a lot if you talk to someone about all the different Bluetooth 5.0 codecs and other Bluetooth formats.
What Are Bluetooth 5.0 Codecs And What Other Bluetooth Formats Are There?
Now that we have established a basic knowledge of all the key terms, let’s get familiar with some popular Bluetooth 5.0 codecs and other Bluetooth formats. As it stands, there are several Bluetooth 5.0 codecs and formats that are used today. Here are some of the most widely used ones.
SBC (Low-complexity sub-band codec)
SBC is the first Bluetooth codec to be introduced. This codec is integrated into the default Bluetooth specifications for audio streaming known as Advanced Audio Distribution Profile (A2DP). In other words, this codec is supported in all Bluetooth devices. If you want to know more about A2DP, then you can also check out this article over here!
SBC has a max bit rate of 345 kbit/s and a sample rate of 48 kHz. Because of these aspects, SBC is not an ideal option for music streaming as users are likely to get very poor quality audio. So, if you see that a headphone only supports SBC codec, its best not to get it.
Sony’s LDAC has quickly become one of the most popular audio codecs in recent history, especially after the launch of the company’s high-end wireless earbuds – Sony WF-1000XM4. However, since this codec has been developed by Sony, only its headphones, earbuds, and Bluetooth audio devices support LDAC. On the other hand, a large number of smartphones support LDAC as the codec has been an open-source project since Android 8.0.
The reason why LDAC has become so popular in recent times is because it offers almost lossless audio quality. Its variable bit rate allows this codec to perform such a feat. But to achieve that, you will need both of your devices to support LDAC, which can be seen as a shortcoming. Typically, LDAC can reach a maximum of 990 kbit/s with a sampling depth of up to 24-bit at 96 kHz.
AAC (Advanced Audio Codec)
If you are an Apple device user, then you should be quite familiar with AAC. This codec is primarily used in iPhones and iPads, as well as YouTube. However, the primary limitation of this codec is that it does not work well with Android devices. In addition, AAC’s file transfer algorithm is based on psychoacoustic models, which means some parts of the audio are trimmed for better compression.
On a technical note, AAC is a lossy codec with a bit rate of 320 kbit/s at 24-bit with a sample rate of 44.1 kHz. Though the specs are nothing to write home about, the quality of the audio depends on how the codec is implemented. When it is implemented correctly, you are bound to get really clear and rich audio quality.
Qualcomm has developed its own proprietary family of codecs known as AptX. This codec has four members: AptX, AptX HD, AptX LL, and AptX Adaptive. Here is a quick comparison between the four codecs to give you an idea of the kind of performance you can expect from them.
|Codecs||Max. Bit Rate||Bit Depth||Max. Frequency|
|AptX||384 kbit/s||16-bit||48 kHz|
|AptX LL||384 kbit/s||16-bit||44.1 kHz|
|AptX HD||576 kbit/s||16, 24-bit||48 kHz|
|AptX Adaptive||420 kbit/s||16, 24-bit||48 kHz|
From the table above, you should have a good idea about the specifications of this family of codecs. Compared to AptX, AptX HD offers a higher bit rate as well as bit depth. And although AptX LL doesn’t seem to stand out much, it has the lowest latency in the family. So, gamers are gonna love AptX LL. Lastly, AptX Adaptive is the most balanced among the rest as it has a good bit rate, bit depth, and sample rate. But for some reason, this codec did not catch on as quickly as AptX or AptX HD.
LC3 (Low Complexity Communication Codec) is a low-complexity audio codec that is designed to deliver good audio quality without sacrificing efficiency. What’s interesting is that it is also developed by Qualcomm. It uses a combination of advanced audio coding techniques and psychoacoustic modeling to deliver high-quality audio at low bitrates. Moreover, it is also designed to be efficient in terms of power consumption, which makes it suitable for users who want to preserve their battery lives.
As for the maximum bit rate, this codec can reach up to 392 kbit/s with a bit depth of 32-bit. And it has a maximum sampling rate of 48 kHz. Overall, there is a lot of potential for LC3 as it is still relatively new in the codec scene. Expect improvements in audio quality, lower latency, economic power consumption, and a new feature where users can share audio across devices.
LHDC (Low Latency and High Definition Audio Codec) is a proprietary audio codec developed by Hi-Res Wireless Audio (HWA) Union and Savitech. It is able to deliver high-quality audio by using a combination of advanced audio coding techniques and psychoacoustic modeling. In addition, LHDC is also designed to be efficient in terms of power consumption. This makes it well-suited for use in battery-powered devices, such as headphones and earphones.
LHDC supports a maximum bit rate of 900 kbit/s with a sample rate of 96 kHz. While these specs are nothing to scoff at, LHDC also offers a low-latency alternative – LHDC LL. This codec is great for gamers as it has a minimum end-to-end latency of 30 milliseconds. And with a bit rate of up to kbit/s with a maximum sample rate of 48 kHz at up to 24 bits, you should have no issues whatsoever when using this codec for your audio requirements.
As one of the biggest manufacturers of smartphones on the planet, Samsung too has its own proprietary codec called Samsung Scalable. This codec is developed by Samsung for its smartphones, headphones, and other audio accessories, and is designed to deliver high-quality audio over Bluetooth while being efficient in terms of computational complexity and power consumption.
The reason why it is dubbed as “Scalable” is because this codec prioritizes stability by continuously making adjustments to the streaming rate. This prevents connection drops and audio stutters. The codec can scale between a bit rate of 88 to 512 kbit/s. And it has a maximum sample rate of 96 kHz with a bit depth of up to 24-bit.
How To Change Bluetooth 5.0 Codec?
Here is how you can change your Bluetooth 5.0 codec in your Android smartphone:
- Go to your Settings
- Tap on About Phone
- Tap on Build Number a few times until you unlock developer options
- Go back and enter developer options
- Find “Bluetooth Audio Codec”
- Select your desired codec
Unfortunately for iPhone users, changing the audio codec is not possible. Apple devices use AAC by default, which works great in most cases.
Summary of Bluetooth 5.0 Codecs And Other Bluetooth Formats
Here is a quick overview of all the technical differences between the codecs mentioned.
|Codec||Min. Bit Rate (kbit/s)||Max. Bit Rate (kbit/s)||Sample Rate (kHz)||Bit Depth (-bit)||Latency (ms)|
|AptX||352||384||48||16||Less than 180|
|AptX HD||576||576||48||16, 24||200|
|AptX LL||384||384||44.1||16||Less than 50|
|AptX Adaptive||279||420||48||16, 24||80|
|LC3||160||392||48||16, 24, 32||N/A|
|LHDC LL||400||600||48||16, 24||30|
|Samsung Scalable||88||512||96||16, 24||N/A|
From the table, we can see a general outline of the most popular Bluetooth 5.0 codecs. However, do take these numbers with a grain of salt, as the latency can vary significantly on the kind of device you use. Also, codecs alone are not responsible for high or low latency.
If you have read this far, then you should have a pretty good idea about all the different types of Bluetooth codecs that are used currently. We hope that this article was able to provide some clarity on some of the jargon that gets thrown around by audiophiles. But do bear in mind, codecs alone are not entirely responsible for the quality of audio you are listening to. Here is a simple rule of thumb you can follow:
- High bit rates are preferable.
- Your phone and Bluetooth device need to support the same codec.
- Prioritize low latency.
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