SBC vs AAC vs AptX: Which is Better Bluetooth Codec

The journey of Bluetooth has come a long way. Before Bluetooth connection was not very capable like today. The earlier version of Bluetooth connection was not capable of transmitting sound like a wired headphone could transmit by the 3.5 mm audio port. But over time it got improved and nowadays Bluetooth audio is gaining popularity. The popularity moved to a point where now technologies like Apple devices and some android devices too removed their audio headphone jack from their devices several years ago. So Bluetooth earphones are now being used normally all over the world.

SBC vs AAC vs AptX Bluetooth Codec

The reason Bluetooth got so much popularity is because of the development of a better Bluetooth codec that enables completely stable streaming without losing any connection. The higher the version of Bluetooth got the better the Bluetooth technologies have become. Especially when some smartphones, such as the iPhone, removed the audio jack for headphones, it led to audio companies producing high-quality wireless devices. Qualcomm aptX code ranks high among other Bluetooth technologies. Besides before buying wireless headphones you need to know about Headphone Tech Specs and supported codecs SBC, AAC, Aptx.

What is a Bluetooth Codec?

The word codec comes from the coder and decoder so is the literal explanation of what the codec is. It refers to the method of encoding and decoding audio or video that has been compressed to make the file size relatively smaller such as a file like mp3 or AAC. In other meaning, it’s basically the process of formatting the zeros and ones of transmitted data. The audio codec is used for transmitting audio from the source device such as a phone, television, computer, etc. to receiver devices like wireless headphones or speakers or any other wireless devices.

There are different types of codecs of audio that have various levels of quality with varying degrees of loss. Using different formats of codecs can also use their own compression methods to maintain the balance between the quality of sound and the audio file’s information package. You may think compression of audio can lower the audio quality which will be not preferable for high-quality audio lovers, it is necessary for the larger file to send and receive from device to device wirelessly.

This means different Bluetooth codecs are compatible with different audio devices and provide different sound qualities and connections between devices. Almost all Bluetooth devices support standardized SBC codec which is Low Complexity Subband Coding. But throughout the history of Bluetooth technologies, the implementation of SBC varied in quality. In order to provide better service to the users of Bluetooth technology many companies have made their own Bluetooth codecs and licensed them to other companies. For example, Apple products use AAC format, which compresses more than Mp3 without losing quality and gives better output. Sony has the LDAC Bluetooth codec and Qualcomm offers the Aptx codec.

Before understanding the Bluetooth codecs and their capabilities you should first understand the latency in Bluetooth.

What is latency in Bluetooth codecs?

The latency or the delay in wireless is the measurement of the time between when a pack of data is sent and that packet of data is received between devices. In terms of Bluetooth, latency is a measurement in milliseconds of time from when audio is sent via Bluetooth and then received and played by the receiver.

Latency time may not be accurate for all devices or environments. It varies on several different factors that include the processing power of the devices, implementation of Bluetooth and codec standards, signal strength, the distance between the sender and receiver devices, and as well as the capabilities of the codecs themselves.

Now depending on these, you can say latency is not an absolute number that always will be the same. We cannot account for environmental factors but we can come to generalize the statement of the capability of individual codecs. But you should know that just because an individual is better at latency than the other it does not mean it will perform better in the real world.

Capabilities of SBC, AAC and AptX codecs

Bluetooth has a limited amount of bandwidth available to transmit audio. Bluetooth connection is also variable depending on different factors like environment, and interference distance between the transmitting device and receiving device, so the audio needs to be compressed so that Bluetooth can send it. Bluetooth codecs encode and decode audio having different types of file compression methods to send as much audio data as possible by available bandwidth and speed.

The codecs differentiate among themselves by bit depth (bits), bitrate (kbps), and sample rate (kHz). The efficiency of the codec can determine the audio quality transmitted by Bluetooth devices. SBC, AAC, and Aptx are the three main codecs the users will come across.

SBC

  • Bitrate: 328kbps
  • Sample Rate: Up to 48kHz
  • Bit depth: 16 bit

SBC (Subband Codec) is the most basic codec which can be found in almost all wireless devices and all Bluetooth headsets with an A2DP profile (Advance Distribution Profile). As it is capable of transmitting up to 328 kbps with sample rates of up to 48 kHz and with 16-bit depth.

It gives a decent quality of audio sound and takes a small amount of processing power. However, the weakness of SBC is, it is a lossy codec with variable bitrate. This means the bitrate is often not achieved to its highest as a result the audio can be inconsistent depending on the situation. This can be much more notable with an inexpensive Bluetooth transmitter.

So while SBC does perform pretty well on its highest quality settings but its variable nature and imbalanced application standards between device manufacturers mean that it is rather a good option or a miss. So even if SBC is available on all Bluetooth devices it should rather be used only when there are no other choices.

AAC

  • Bitrate: Up to 320Kbps
  • Sample Rate: 44.1kHz
  • Bit depth: 16-24 bit

AAC (Advanced Audio Codec) is more efficient than mp3 and results in lower bit rates and file sizes for the same audio quality as mp3. It supports bit rates of 320kbps although in most cases it’s 256kpbs with sample rates of 44.1 kHz and with up to 24-bit depth. Apple has the best implementation of AAC and AAC is the preferred Bluetooth audio codec for IOS devices. But some Android devices support AAC but often don’t perform very well. It is for this reason AAC probably shouldn’t be used on Android when there are other choices.

You may not find AAC-implemented devices most often but thanks to Apple it is rather a popular codec.

AAC implemented device

Aptx

Qualcomm aptx
  • Bitrate: Up to 384kbps
  • Sample Rate: 48kHz
  • Bit depth: 16 bit

Aptx codec is ideal for audio applications as it performs encoding more efficiently than SBC. So For most wireless Audio devices, it is a much preferable Bluetooth codec. Qualcomm’s Aptx comes in different varieties developed for different purposes.

The standard Aptx, Aptx LL (Low Latency), Aptx HD for high-quality audio, Aptx Adaptive offers a balance of lower latency and higher quality, causing its bitrate stays at a high level.

There is also a version name Aptx Lossless, which combines the best qualities of Aptx HD and Aptx Adaptive, which is a variant to keep an eye on. But Aptx Lossless implemented devices haven’t hit the market yet. 

Among these variations, Aptx HD is widely used for the best performance of Bluetooth devices.

What is Aptx HD?

Qualcomm aptx HD

Aptx HD is the extension and top-quality version of Aptx. It was introduced to make use of Bluetooth for better sound quality. Even though it uses the same ADPCM technology, It provides higher bit depth and less noise of audio. The HD version also improves the quality of wireless, as a result, the sound maintains its details, comparing other materials without compression. The capabilities of Aptx HD are:

  • Bitrate: Up to 576kbps
  • Sample Rate: 48khz
  • Bit depth: 24 bit

As you can see the bitrate and the bit depth of Aptx HD are better than the Aptx and also far exceed the SBC codec.

SBC vs AAC vs Aptx which one is the best?

After understanding the capabilities of SBC, AAC and Aptx you can differentiate among them on the basis of their capabilities. As we discussed earlier the SBC is the very basic codec and is supported by almost all Bluetooth devices, AAC is the preferred codec for Apple devices, and Aptx with its Aptx HD version an ideal and top-quality codec for Bluetooth devices.

Now for which one is better among SBC, AAC and Aptx on the basis of capabilities alone, the Aptx HD version of Aptx with a very high bitrate and bit depth should win the comparison. In terms of technologies, however, it should be noted that higher-quality are less stable than lower-quality codecs and are more vulnerable to range and interference issues.

So by comparing all the factors of their capabilities:

BitrateSample RateBit depth
SBC≤328 kbps48 kHz16 bit
AAC≤320 kbps44.1 kHz≤24 bit
Aptx≤384 kbps48 kHz16 bit
Aptx HD≤576 kbps48 kHz24 bit

For Android users as discussed above AAC may not be the best option for them to check out for, Cause for Apple has the best implementation of AAC and it can not be said for Android as well. So for android users, SBC and Aptx can be better options to choose between.

SBC vs Aptx

In terms of capabilities, Aptx has better and Aptx HD version has an even much higher bitrate and bit depth than the SBC. In theory, the bitrate of SBC codec can achieve up to 328 kbps, which isn’t bad for sound quality. It also uses low processing power which is an advantage and the A2DP audio profile allows wireless transfers of audio formats such as MPEG and ATRAC. However, supports for these formats are optional and depends on the wireless devices. But SBC can not maintain this much bitrate because of its variable nature.

The Aptx codec, on the other hand, has a better signal-to-noise ratio in frequency ranges and also better performance when it comes to the latency of Bluetooth. This codec was developed to ensure the quality of audio in all products compatible with its format. Aptx transmits audio with up to 384 kbps/16-bit 48kHz. which means a 4:1 compression ratio compared to lossless files that include enough information for wirelessly carrying files like the best MP3 formats.

Another interesting fact is Aptx uses ADPCM (Adaptive Differential Pulse-Code Modulation) which divides the audio frequency into four bands, each with its own bit depth and signal-to-noise ratio. This feature of Aptx is superior to SBC for sending compressed audio via Bluetooth. As we said Aptx has a better signal-to-noise ratio than SBC, with about 5kHz more capacity, we can get better details on the audio when listening with the headphone if the source audio has good quality.

Qualcomm codec has also a faster conversion speed than SBC which let the audio information packets transfer more efficiently. This means it has lower latency which is very important for users wanting high quality without delay sound when playing games or watching movies.

SBC vs AAC vs Aptx which one is better code on latency? 

We already discussed above that the latency varies on several different factors like processing power of the devices, implementation of Bluetooth and codec standards, signal strength, the distance between the sender and receiver devices, and as well as the capabilities of the codecs themselves. Because latency is so variable and entirely depends on several different factors, comparing SBC, AAC and Aptx on latency alone won’t satisfy which codec is better for latency performance. However, a generalized statement of each codec’s latency can give an idea of which can be better at handling latency.

SBC has around up to 250ms latency, which varies on the devices, the environment, and other factors discussed above.

AAC has around 150ms latency on the Apple device, again varying on devices and environment and other factors. Also as for Android, the latency of AAC can be much higher.

Aptx has around 150ms latency, which varies on the devices, the environment and other different factors discussed above.

This data of latency may not be accurate for all devices and environments. As a result, Bluetooth codec’s performance can’t be determined by the latency alone.

Conclusion

when it comes to buying Bluetooth devices you should understand the Bluetooth codecs and which codecs are supported by the device. We can say that the Qualcomm aptx has a good number of advantages over SBC that 70% of current Android devices support aptx and for Apple users, they have the best-implemented AAC codec. However, these codecs can’t ensure the highest level of sound quality if the Bluetooth devices are not of good quality. But these codecs help a Bluetooth device with good quality achieve the best performance.

James

James

Hi, this is James, a tech specialist and a core member of the TrioTeam. I like to research and write content about various interesting things especially tech-related stuff, and also have an interest in philosophical discussion. I have been writing solutions for technical problems, how-to tutorials, technology reviews, tools and websites, and so on for TrioGuide.

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