SBC vs. aptX: Which Bluetooth Codec Is the Best?

While most of us might not pay any attention to the quality and speed of our Bluetooth devices, it can play a major role in our enjoyment of media and the crispness of our music playback. Especially if you consider yourself an audiophile, the audio codec used in your device is paramount for being able to fully appreciate a device.

Even though there are many of us who don’t even know what a codec is, it’s a great thing to know before purchasing Bluetooth devices to ensure that they will be able to do everything you need.

Let’s take a look at some of the most popular audio codecs in Bluetooth, such as SBC and aptX, so we can compare their features and benefits.

What Is a Codec?

If you’re not well versed in the world of sound terminology, you likely don’t have much of an idea of what a codec is. 

A codec is a device or program that compresses data for transmission and decompresses the received data. Basically, it’s a way of being able to transfer data quickly and efficiently from one location to another.

There are multiple different types of codecs, and they each can have an effect on the original quality of an audio source. For example, lossy audio is a compression technique that does not decompress audio files to their original file size. This is a great way to compress many audio files into a smaller storage space, but it results in a lower quality sound.

Compare this to lossless audio, which decompresses audio files to their original data amount after having been received. This is ideal for professional audio settings and is able to output high fidelity sound that most audiophiles love to hear. FLAC and ALAC are popular lossless formats.

Finally, there is uncompressedaudio, in which the quality is neither decompressed nor compressed, allowing the audio to sound the same as when it was recorded. PCM and WAV formats are examples of uncompressed files.

Lossless and uncompressed audio formats are possible through a wired connection, which allows for more secure and bulky data transmission than wireless devices. Because of that, Bluetooth must use alternative methods to maintain quality sound without too much of a delay.

What Is SBC?

SBC stands for Sub-band Coding. It is the mandatory and default codec for all Bluetooth headphones with an Advanced Audio Distribution Profile. It has a pretty decent audio quality without needing too much processing power to encode or decode the source files. However, the quality can be inconsistent at times.

This inconsistency is mostly noticeable in the form of an audio delay between the master Bluetooth device and its peripherals. SBC operates at a latency of between 170 and 270 milliseconds. While this might not be noticeable when listening to music, it is extremely noticeable when watching a television show or movie, as the character’s dialogue will be out of sync with their mouths.

With that said, this is a standard codec for the majority of Bluetooth devices.

What Is aptX?

This is an optional codec for some Bluetooth devices. It is ideal for demanding audio applications, as it is able to encode and decode more efficiently than SBC. It has much lower latency than SBC as well, meaning that syncing issues are not as common.

There are two common subdivisions of aptX as well: aptX HD and aptX low latency.

AptX HD

The HD version of aptX focuses on heightening the audio’s quality. AptX HD operates with 24-bit wireless tech to give some of the highest consistency sound possible in a Bluetooth device.

It is the closest that you can get to high resolution audio without using a wired source.

AptX Low Latency

AptX low latency focuses on lowering the latency, or synchronization delay, that is common among Bluetooth peripherals. It improves end to end speed of audio transmission, virtually eliminating lip-syncing issues on screen.

Sound Quality: SBC vs aptX

Although Bluetooth devices aren’t able to replicate the same quality sound as most wired systems, you can get pretty close depending on which codec you utilize.

The standard versions of both SBC and aptX have a sound quality that is extremely similar, meaning that untrained ears aren’t very likely to notice a difference. But if you frequently listen to music or make a living revolving around sound, you’ll definitely see a difference in quality when aptX HD is introduced.

Qualcomm, the company behind aptX, claims that their codec can achieve near CD quality, which is perfect for people who really care about the way their music sounds. 

Since aptX HD was engineered with audio quality in mind, it is able to get much closer to uncompressed sound when compared to SBC. So, in short, aptX has a better sound quality, but only when the product uses aptX HD.

Latency: SBC vs aptX

It can be extremely frustrating to watch a show when all of the sound is the slightest bit out of sync. This is a common occurrence when wireless speakers are used to transmit Bluetooth audio from a television or projector screen.

As previously mentioned, SBC has a latency between 170 and 270 ms, making sync delay entirely possible. But the standard version of aptX has a latency of only 60-80 ms, which makes out of sync sound a lot less noticeable.

But even at 60-80 ms, those with trained eyes will be able to notice a little bit of a delay. This is where aptX low latency can really shine, because it was specifically designed to decrease audio delay. AptX low latency has an improved latency of just 30-40 ms, making out of sync lips virtually non-existent.

A high bitrate code is going to help you out here as well. A bitrate is how much audio data that your device can transfer per second via Bluetooth—a high bitrate is going to give you higher sound quality but less compression, and vice versa. How does this fit in? 

SBC has a low bitrate code—in fact, one of the lowest out there. In contrast, aptX has a much finer bitrate, meaning that everything can keep running smoothly to keep your sound crisp and clear. 

So if you’re one to use wireless speakers to watch different forms of entertainment, a device that utilizes aptX low latency from Auris is definitely the way to go.

Compatibility: SBC vs aptX

While aptX has some features that are missing in SBC, keep in mind that it is a newer codec by comparison. Because of this, you may notice that some devices are not compatible with one another, as one may not operate using aptX.

Since SBC is the default codec, it is also the most commonly used. This means that you are more likely to find two products that are compatible with one another if you were to focus your peripherals on SBC rather than another codec.

With that in mind, this usually isn’t too much of an issue, and the newest version of Android even lets you change the Bluetooth codec within the settings.

Are There Any Other Bluetooth Codecs?

While SBC and aptX are definitely the most widely used codecs, it doesn’t mean you might not see others labeled on your compatible devices.

Another fairly well-known codec isAAC (Advanced Audio Coding).This is a lossy audio that is perfect for smartphones because of the small file size that it transmits after compression. While it won’t provide the same quality as a wired connection or aptX HD, it still is a pretty decent way for audio to be transmitted.

Sony has also created its own wireless audio codec called LDAC,which is capable of transmitting high resolution enhanced wireless data. LDAC maintains maximum bit depth and frequency range during transmission, making for an extremely high-quality listening experience. It can transmit about three times the data as SBC.

The Final Verdict

While Bluetooth technology is an all-around necessity for modern living, certain audio codecs might be more sorted to our own personal preferences. SBC and aptX are both some of the most widely used codecs for wireless technology.

As far as sound quality, aptX has a slight edge, especially when using aptX HD, which is a version of aptX specifically engineered for better audio quality. However, most people may never notice a difference in quality between them.

For latency, or sync delay, aptX is able to stream much more quickly than SBC. AptX low latency can stream at just 30-40 ms when compared to SBC’s 170-270 ms speed. This makes the former a much better option, especially when watching movies or tv shows.

Despite being less compatible, aptX is a bit better than SBC, purely because it has been crafted with certain limitations in mind. Regardless, you can experience the enjoyment of wireless technology with either of these codecs.

Sources:

Web audio codec guide – Web media technologies | MDN

Lossy compression (article) | Khan Academy

Introduction to audio compression for beginners | Adobe

Understanding Bluetooth codecs | Sound Guys