Bluetooth Audio Codec Compared: Which Is Best?

With the explosion of wireless headphones and earphones, we hear more and more often about Bluetooth audio codec: SBC, AAC, aptX, or LDAC are just some of the more common names, but the list is long and not easy to navigate. Bluetooth codecs mainly affect the audio quality the signal latency consumption and can influence the choice of a product, even considering that each device supports different codecs.

What is a Bluetooth audio codec

Let’s start from the basics: when we talk about audio codecs we mean software capable of encoding and decoding an audio signal and, if necessary, compressing it to make it take up less space.

One important thing to point out is that codecs are not born with music via Bluetooth: they are a necessary tool to transform an audio signal into a numerical sequence (to code, in fact), therefore a type of data that can be stored on a digital medium or transmitted.

To be clear, even the very famous MP3 which became famous for the homonymous format with which music was stored, is an audio codec, used for compression.

Speaking of compression, when we talk generically about audio codecs, there are formats uncompressed and formats compressed where the former is obviously much bulkier in size (the most famous example of uncompressed audio is Microsoft’s WAV).

Compressed formats, which reduce the file size, can in turn be divided into

  • lossy with data loss
  • lossless without data loss

The most famous of the lossless codecs is certainly the Free Lossless Audio Codec (FLAC)a free and widely used codec for high-definition music.

The FLAC (Free Lossless Audio Codec) logo
The FLAC (Free Lossless Audio Codec) logo

However, when we talk about audio via Bluetooth, a loss of data is always expected: in other words, all Bluetooth audio codecs are lossy and this is the main reason why wireless solutions are not very popular with sound purists.

To be honest we begin to take the first steps for a lossless codec (aptX Lossless) but there are no devices on the market that support it yet.

Bluetooth
Bluetooth

In any case, in recent years great strides have been made with audio codecs: so let’s see which are the most famous, what features they have, and which devices support them.

Keep in mind, however, that the reported data are theoretical specifications and that each smartphone can behave differently according to the manufacturer’s specifications; furthermore, consider that the values ‚Äč‚Äčindicated for latency (ie the delay between signal and audio) are only indicative.

SBC (Sub-band Coding)

  • Maximum Bitrate: 345 kbps
  • Bit depth: 16 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 200ms

SBC is the most basic Bluetooth audio codec, supported by virtually any smartphone and any headset. It is the default codec for Bluetooth audio transmission (defined by the Bluetooth A2DP profile) and it is the one that all devices must necessarily implement.

It can be used freely, without a license.

SBC is the basic codec used on all Android smartphones and is the one that is used in case of problems with other codecs.

It has pretty high latency, so it’s not the most recommended codec for gaming.

AAC (Advanced Audio Coding)

AAC is the default codec for iPhone and iPad
AAC is the default codec for iPhone and iPad
  • Maximum Bitrate: 320 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 44.1 kHz
  • Latency: ~ 200ms

AAC is a codec that can offer better performance than SBC but is more demanding in terms of performance and consumption. It is the codec used by YouTube and is the reference codec for products Apple (and it works less well on Android).

While iPhones and iPads implement a maximum bitrate limit of 250 kbps for AAC, AAC’s performance is significantly better than SBC’s on iOS-based devices.

Again the latency is relatively high.

aptX (aptX Low Latency, aptX HD and aptX Adaptive)

aptX is a codec family Qualcomm-owned Bluetooth, which manufacturers of smartphones and accessories can use under license (for a fee).

For this reason, although they are very common, it is not obvious to find an aptX codec on your devices. Support for aptX codecs is pretty common on Android devices, but iPhone and iPad do not support aptX.

Unlike the previous two, in this case, we are talking about a family of codecs, consisting of 4 different codecs: aptX, aptX HD, aptX Low Latency, and aptX Adaptive.

AptX codecs are owned by Qualcomm
AptX codecs are owned by Qualcomm

aptX

  • Maximum Bitrate: 384 kbps
  • Bit depth: 16 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 180ms

aptX HD

  • Maximum Bitrate: 576 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 200ms

aptX Low Latency

  • Maximum Bitrate: 384 kbps
  • Bit depth: 16 bit
  • Maximum frequency: 44.1 kHz
  • Latency: ~ 40ms

aptX Adaptive

  • Maximum Bitrate: 420 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 80ms

The basic version of aptX is the most common alternative ad SBC on Android: can bring slightly higher audio quality (especially on high frequencies) and slightly reduced latency.

Although the basic variant of aptX is clearly the most widespread, the other versions are certainly more interesting, especially for those with specific needs: aptX HD offers higher sound quality and is more suitable for audiophiles, while aptX Low Latency minimizes latency and it is the most recommended codec to play.

In the end, aptX Adaptive is somewhere in between the last two: as the name suggests, it automatically adapts the bitrate (which can scale a lot) to ensure the highest possible audio quality at the lowest possible latency.

Snapdragon Sound
Snapdragon Sound

aptX Adaptive is the codec on which Qualcomm has been betting the most in recent years: it will be the reference codec for Snapdragon Sound and will integrate Qualcomm’s aims for lossless audio: aptX Lossless arrives the first lossless Bluetooth audio codec.

We specify that each of the aptX must be implemented individually by producers; in other words, having aptX support does not mean that you also support aptX HD or aptX Adaptive.

LDAC

  • Maximum Bitrate: 990 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 96 kHz
  • Latency: ~ 200ms

LDAC is Sony’s proprietary codec: Originally only available for the Japanese company’s smartphones, it has been integrated into the Android Open Source Project (AOSP) starting with Android 8 Oreo and can now be implemented by any manufacturer.

LDAC is not supported by iPhones.

LDAC
LDAC

It is a specialized codec for high-definition audio that stands out for the possibility of dynamically changing the bitrate (like aptX Adaptive).

The maximum bitrate of 990 kbps is the highest ever available in Bluetooth codecs (and is the one that comes closest to the 1,411 kbps of wired Hi-Res audio); the other two bitrates are 330 kbps and 660 kbps.

Along with LHDC, it is one of two certified Bluetooth audio codecs as Hi-Res Audio Wireless from the Japan Audio Society.

Hi-Res Audio Wireless
Hi-Res Audio Wireless

LDAC is a codec available under license (upon payment to Sony, therefore), and, also considering the considerable technical requirements, there are not many headphones that implement it.

However, thanks to the good name that the codec has carved out among enthusiasts, in recent years other companies besides Sony have begun to integrate it into their devices (a list of manufacturers that have integrated the LDAC codec is available at this address under the heading LDAC compatible products other than Sony).

LHDC

  • Maximum Bitrate: 900 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 96 kHz
  • Latency: ~ 200 ms

LHDC is a codec developed by the Chinese company Saviteche currently being promoted as a reference codec by the Hi-Res Wireless Audio (HWA) Union, an association of companies formed that produce audio products precisely to promote LHDC. Among the numerous companies, Huawei, Sennheiser, Fiio, Pioneer, and 1More are also part of the HWA union.

LHDC stands for Low Latency High-Definition Audio Codec and, like LDAC and aptX Adaptive, it is a codec that automatically scales the bitrate as needed. The available bitrate ranges are 400 kbps / 560 kbps / 900 kbps.

Like LDAC, it is especially appreciated by lovers of high quality and, together with LDAC, is one of two Bluetooth audio codecs certified as Hi-Res Audio Wireless from the Japan Audio Society.

In the smartphone sector, it is implemented by OPPO, Huawei, Xiaomi, and Redmi, even if from Android 10 it is integrated into the Android Open Source Project (AOSP) and can therefore be implemented by any manufacturer. LHDC is not supported by iPhone.

LLAC

  • Maximum Bitrate: 600 kbps
  • Bit depth: 16-bit, 24 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 30 ms

LLAC (Low Latency Audio Codec), also called LHDC LL, is a variant of LHDC optimized for low audio latency. It is practically the only codec that guarantees latencies comparable to those of aptX Low Latency.

As well as LHDC, is mainly implemented by OPPO, Huawei, Xiaomi, and Redmiand since Android 10 it is integrated into the Android Open Source Project (AOSP).

LC3

  • Maximum Bitrate: 345 kbps
  • Bit depth: 16-bit, 24-bit, 32 bit
  • Maximum frequency: 48 kHz
  • Latency: ~ 20 ms

LC3 (Low Complexity Communication Codec) will be the default Bluetooth audio codec of the next few years and was conceived as a successor to SBC, with respect to which it offers significantly better performance and lower consumption.

It is the first (and only) Bluetooth codec to support the Bluetooth LE Audio profile only available with Bluetooth 5.2 and above: LE Audio stands for Low Energy Audio and it is a radically different communication profile from classic Bluetooth.

Thanks to this new transmission profile, the LC3 is able to offer a much higher audio quality than SBC with the same bitrate, but also a very low latency, comparable to or even lower than the aptX Low Latency or LLAC codecs.

Bluetooth Codec Comparison Standard Stereo Listening Test
Bluetooth Codec Comparison Standard Stereo Listening Test

Currently, there are not many smartphones that support LE Audio and LC3 and the most virtuous examples are the new Pixel 7 and the latest iPhones. As for the headphones, the new one’s 2nd generation AirPods Pro is the first (and among the very few) to support LC3 codecs.

Also, read about New Update For AirPods Pro 2

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Abram left his e-business studies to devote himself to his entrepreneurial projects. In 2017, he created the company Inbound Media and wrote articles about high-tech products for his Chromebookeur site. In 2019, Chromebookeur was renamed Macbound and became a general purchasing advice site. Today, Abram manages the development and growth of Macbound, surrounded by a young and talented team.

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