Comparing Bluetooth codecs – SBC vs AptX vs LDAC vs LHDC vs AAC vs LC3

In this post, we are comparing Bluetooth codecs to better understand their pros and cons.

The Bluetooth audio transmission has been one of the amazing options for wireless audio. The system has been integrated effectively into almost every smartphone and tablet. It has become quite simple and easy to stream your content with comfort.

Also Read: Comparing HDMI ARC vs Optical 

However, if you are looking forward to the best attainable transmission, it is always important to focus on the best codec for perfect and assertive communication. Therefore, we will try finding the best Bluetooth audio codecs you need to focus on for an enhanced degree of experience.

How does a Bluetooth transmission work?

A Bluetooth transmission requires the two devices to be paired to one another. Once they are connected, they would start communicating. When it comes to audio transmission, Bluetooth technology uses around five different transmission modes. These modes are referred to as codecs.

When the transmission conditions are not ideal, the Bluetooth devices drop to the least effective codecs and move to the next one. So, for example, when you stream the content from Spotify, Deezer, Qobuz, Google Music, or Apple music, the stream is automatically recompressed according to the codec selected by the emitting and receiving devices.

Which Bluetooth codec should you choose?

Before deciding which Bluetooth audio codec you should choose, it would be essential to find everything about the codecs.

The most popular codecs that you would find on most devices are as follows:

• SBC
• AptX (HD)
• AptX Adaptive
• LDAC
• LHDC
• AAC
• LC3

To understand the differences between the Bluetooth wireless codecs, we first need to understand key terms: bit depth, sample rate, bit rate, latency, and compression. Bit depth is the number of bits (basic digital communication information unit) in each sample.

This corresponds with the resolution of each sample, as a higher bit depth will create higher-resolution audio reproduction. The sample rate determines the number of samples per second taken from an audio signal to create a digital signal. Bit rate refers to the number of bits transferred per second. We can use bit depth and sample rate to determine the bit rate by using the equation:

SAMPLE RATE x BIT DEPTH x NUMBER OF CHANNELS (usually 2 for left and right) = BITRATE.

Using this equation, let’s calculate the bit rate of your standard CD. We can then use this information as a standard of reference when looking at different Bluetooth codecs. CDs usually have a sample rate of 44,100 samples per second and a bit depth of 16-bit. They will also have two channels for your left and right audio. When we multiply these together, we get 1,411,200 bits per second or 1,411.2 kbps.

The last two terms we will want to understand are latency and compression. Latency is the time it takes for a signal to travel through a system.

The most common latency for Bluetooth transmission is audio output latency, which is the time it takes for the sample to play through an audio device after the sample has been created. Compression is a way to make audio data smaller so it can more easily be transferred wirelessly.

For example, a Bluetooth codec may reduce the CD-quality 1,411.2 kbps rate to about 300 kbps. This does result in some loss of audio quality (such as missing higher frequencies that the human ear is less likely to detect). Still, the stability of the stream from your phone or computer to your headphones is increased due to less data being transmitted.

Source – Audio Technica

Let us explore each of these codecs and find more details about them –

SBC

SBC is a codec that stands for Low Complexity Subband Codec. This has been considered to be the basic codec for the optimum audio transmission. When the radio conditions are good enough, the codec offers you a bitrate of 350 kb/s that would provide a decent audio quality.

However, in case the bit rate drops below around 128 kb per sec, you may begin feeling a few artifacts at higher frequency audio. In addition, your Bluetooth headphones will start producing a hissing sound.

The SBC codec is most likely observed on the cheaper headphones. It is a part of the Advanced Audio Distribution Profile (A2DP). The best part is that the codec is used without any license. On the other hand, the codec can cause a loss of quality that can be pretty conspicuous.

The codec may not be the right choice for music streaming. However, it is mandatory to include SBC for the manufacturers. In the absence of other possible high-end codecs, the headphone falls back to the SBC codec.

AptX (HD)

The AptX HD was a codec developed by Qualcomm and has been an excellent option for most of the expectations and needs that you may have. The name AptX stands for Audio processing technology.

The higher bit rates and lower latency would make it one of the choicest options for practically every expectation and need that you may have in your mind. The AptX HD codec supports the 24-bit resolution. You would be able to access the maximum bit rate of 567 kilobits per second at a sampling rate of 48 kilohertz.

The latency offered by the codec is between 170 and 270 milliseconds. It should be one of the unique options for your needs for the best gaming experience. The bitrate of 576 kb/s is one of the enormous advantages that you stand to gain with the AptX HD codec.

One of the disadvantages of the AptX HD codec is that it is not supported on iOS. Therefore, if you connect a set of AptX headphones to an iPhone or any other iOS device, you would not get access to this codec.

AptX Lossless

This is yet another variation of the AptX codec. This standard was developed in 2021 by Qualcomm and has been one of the unique options for an enhanced experience over the existing standard. You will be able to access a completely lossless audio transmission that provides you access to a CD-quality audio performance.

The codec provides you access to offers 44.1 kHz at 16-bit. That would make it suitable for most premium audio streaming devices. One of the issues can be that the codec requires support both on the receiver and transmitter. That would make it a difficult task.

However, Qualcomm is confident that this would be possible on a larger scale in the days to come. There have been practical compatibility on most modern-day devices.

AptX Adaptive

Yet another variation of the AptX codec, the AptX Adaptive, is a successor for the initial AptX codec. However, you may not find it a universal standard on most Bluetooth headphones.

However, as the name itself should be indicative, you would find that it is adaptable to different conditions, and it will work with almost all the various AptX standards.

The standard also provides you with a low latency mode that would make it suitable for most smartphones out there if you are fond of streaming movies. It can also be an excellent codec for mobile games.

You will get access to very high bit rates of 279 kilobits per second to 420 kilobits per second. The backward compatibility with AptX and AptX HD would make it a genuinely formidable choice ever.

LDAC

The LDAC was a standard that Sony developed. It can be an excellent codec for reducing the losses in the audio quality more effectively. Therefore, it has been regarded as the perfect choice for the ideal streaming of music wirelessly.

The codec is found on most Sony headphones, including Sony WF-1000XM4 or the Sony WH-1000XM4. You will gain access to a max of 990 kilobits per second with a sampling depth of 16-bit at 48 kilohertz.

LDAC has been a part of AOSP (Android Open-Source Project) since the days of Android 8.0, and thus you would find it incorporated and supported on almost every modern device in 2022.

Once again, the iOS devices do not support the LDAC codec, and you will not be able to gain the benefits of the codec if you connect a headphone with the LDAC codec onto an iPhone.

LHDC

The next standard, LHDC, is one of the immaculate options with the higher bitrates. The new codec has been ready since Android 10 and is incorporated on most devices. However, you may not find it as widespread as it was expected.

The technical specifications, such as bit rates of up to 900 kilobits per second in 24-bit definition and sampling rates of 96 kilohertz, would make the codec quite impressive. However, it is yet to see a broader adaptation by the manufacturers.

AAC

In case you are using an iPhone or any other iOS device, you would find the AAC codec being used predominantly on them. This is because apple devices invariably use the AAC audio compression, the format used on iTunes and Apple Music.

The quality in terms of the AptX and AAC may be much negligible, and you will find that there is no compression applied to the audio performance for the audio. The AAC standard stands for Advanced Audio Codec. The codec does support 320 kilobits per second at 24-bit and 96 kilohertz.

The psychoacoustic models that AAC depends upon are what would make it a formidable choice for the best file transfer. If you are on an iOS device, it is always a great idea to opt for AAC-compatible headphones.

LC3

Last but certainly not least, the LC3 codec made its entry with Bluetooth 5.2. However, the new codec is still a niche and needs to go a long way before being one of the mainstream codecs. It is designed as a successor to the SBC standard.

However, it still awaits development and adoption. Therefore, you may need to wait a while before the codec is seen to be available in a more widespread way.

The Concluding thoughts

So, which among those codecs would we consider the best? That may not be something that we would be able to pinpoint. There are several complex comparisons and technologies involved, and each of them has its own positive and negative points.

The LDAC standard may be an excellent option for most of the needs that you may have in terms of a premium streaming service. In addition, the AptX HD standard can be a superb choice for striking the right balance in terms of best compression and audio quality.