Some smartphone corporations are bringing again the headphone jack, but others stay staunchly against reintegrating it. Whether or not or not your telephone helps wired audio, there’s no denying the comfort of going wi-fi. Having fewer wires muddle my workplace is a aid, however wi-fi audio introduces a bunch of recent considerations. Now, let’s get you on top of things on the what’s what of Bluetooth codecs.

This text comes from the audio consultants at our sister web site SoundGuys. Take a look at their in-depth breakdown right here

Replace, Could 19, 2021: This text was up to date to deal with high-res music streaming service compatibility with Bluetooth merchandise.

Bluetooth codecs: What it’s best to know

Earlier than breaking down the assorted wi-fi codecs, we have to set up working definitions for a couple of phrases and to cowl a couple of ideas.


  • Pattern fee (Hz): the variety of information factors per second in an audio file. To seize a given frequency precisely, you should seize two samples. This implies audio is sampled at twice the restrict of human listening to (~20Hz). Excessive-res codecs are exported at 96kHz or higher.
  • Bit depth (-bit): the variety of bits per audio pattern dictates a file’s decision. CD high quality is 16-bit, whereas DVDs and Blue-ray discs might assist 24-bit audio. Identical to pattern fee, the next bit-depth yields bigger recordsdata.
  • Bit fee (kbps): that is the variety of bits processed per unit of time, which is often measured in seconds. We usually document this as both kilobits/second (kbps) or megabits/second (Mbps). Bit-rate is calculated by the pattern fee x bit-depth x channels.

Switch charges: there’s greater than meets the attention

Graph showing Android smartphone Bluetooth Codec Latency

Bluetooth information switch charges are unstable. SoundGuys has demonstrated this on the subject of Sony’s LDAC and Android’s encoding of AAC together with its overarching latency points. When an organization advertises a switch fee for its codec, it’s doubtless not a relentless fee. Fairly it’s the optimum bit fee, and your streaming velocity might by no means attain that most if circumstances aren’t always optimum.

Anybody who completely makes use of true wi-fi earbuds and subscribes to lossless music streaming companies like Amazon Music HD, Apple Music, and soon-to-be Spotify, received’t be capable to take full benefit of high-resolution playback. Once more, Bluetooth transmits lossy audio, so your smartphone can’t talk each bit of information to your favourite Bluetooth earphones. There are even some limitations to wired playback for those who use the AirPods Max with the Lightning-to-3.5mm cable and Lightning audio adapter, due to information misplaced throughout the re-digitization course of. Solely a direct TRRS connection can switch 24-bit/48kHz audio and higher.

Microsoft Surface Earbuds true wireless earbuds open case iphone 12 mini

Lily Katz / Android Authority

What’s extra, Bluetooth gadgets have a decided connectivity vary, often three meters for headphones. The farther you progress out of your telephone, the extra interference a sign has to fight. This interference manifests as bodily boundaries (e.g., partitions, folks, air) and as different resonant frequencies (e.g. radio waves and Wi-Fi indicators).

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Begin right here: Headphone shopping for information: Every little thing you should know

One thing else to concentrate on is psychoacoustics. That is the examine of how people understand sound and is profoundly difficult. To abbreviate the matter: a psychoacoustic mannequin is utilized to digital media. It determines what information factors will be compressed or deleted with out notable degradation of sound high quality. If you wish to impress your mates at Wednesday evening trivia, inform them of how psychoacoustics held the door for the MP3 format and compression, which has influenced subsequent audio codecs.

What’s a Bluetooth codec?

Congratulations: you’ve handed Wi-fi Audio 101 with flying colours. Now let’s apply that information.

A codec determines how Bluetooth is transmitted from a supply (e.g. smartphone, pill, or pc) to your headphones. Regardless of the codec, it’s liable for encoding and decoding digital audio information right into a specified format. The purpose is to transmit a high-fidelity sign on the minimal bit fee. Doing so minimizes house and bandwidth necessities for storage and playback. As you will have guessed from skimming the sooner definitions, a low bit fee leads to higher compression and diminished audio high quality. In the meantime, a excessive bit fee leads to much less compression and higher audio high quality.

Bluetooth’s biggest hindrance is its restricted bandwidth, which can lead to connection hiccups.

Your intestine response could also be to favor audio high quality over compression. Nonetheless, as final week’s fortune cookie knowledgeable me, there’s a time and place for every thing. For example, in a extremely trafficked space, a low bit fee might make connection energy extra steady. Certain, it’s on the expense of sound high quality and accuracy however in such settings, say a subway automobile or gymnasium, you’re unlikely to reap the advantages of high-quality codecs anyway.

Sifting by Bluetooth codec alphabet soup

Low-complexity sub-band codec (SBC)

The JLab GO Air cheap true wireless earbuds with the earbuds outside of the case on a mulch pile, almost obscured by leaves in the foreground.

Lily Katz / Android Authority

The low-complexity sub-band codec (SBC) is the the bottom frequent denominator of Bluetooth codecs. It’s the Bluetooth Particular Curiosity Group’s (SIG) naked minimal requirement for the A2DP profile, which determines how audio could also be streamed between gadgets. SBC was initially designed to acquire satisfactory audio high quality at medium bit charges, thus minimizing streaming complexities. It’s engineered to accommodate Bluetooth bandwidth limitations and variable processing energy throughout gadgets. Switch charges (most: 320kbps) are manageable on the expense of information loss.

Qualcomm aptX, aptX HD, aptX adaptive, aptX LL

Then there’s Qualcomm’s host of aptX codecs: aptX, aptX Low Latency (LL), and aptX HD; as soon as aptX Adaptive rolls out, it should substitute aptX LL. These codecs are most related to Android customers. They reduce streaming latency, however the fee at which lag decreases depends upon what smartphone is used. Customers ought to look out for headphones and earbuds that assist aptX if they need extra correct and detailed audio. aptX alone helps 48kHz/16-bit LCPM audio information (352kbps), whereas aptX HD helps 48kHz/24-bit LCPM audio information (576kbps). With that in thoughts, each codecs are nonetheless lossy.

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For now, if in case you have an iPhone, aptX is irrelevant as iOS gadgets solely assist SBC and AAC.

Superior audio coding (AAC)

A chart showing the AAC Bluetooth codec's performance on the Huawei P20 Pro, Samsung Galaxy Note 8, LG V30, and Apple iPhone 7.


The superior audio coding (AAC), is the usual for lossy digital audio compression. It’s additionally the license-free normal for YouTube and is Apple’s most popular mode of switch. iPhone customers profit most from AAC’s hi-res playback, which has tops out at 250kbps.

Though Android helps AAC, its efficiency is severely underwhelming due to inconsistent streaming high quality. This isn’t to criticize AAC, although; as an alternative it’s as a result of Android OS has but to ship on a common means of dealing with AAC. This can be a power-hungry codec which Apple can handle due to its gate saved ecosystem.


A photo of the Sony WH 1000XM4 Headphones Connect app on a smartphone.

Adam Molina / Android Authority

Sony’s LDAC appears promising. Its variable bit fee is sensible in idea and will persistently switch thrice the info of SBC. Nonetheless, in apply, this isn’t the case. LDAC has three modes: 990kbps, 660kbps, and 330kbps. The 2 highest bit charges lose constancy above 20Hz, and LDAC (330kbps) is outperformed by each aptX and SBC. Whereas the choice for LDAC 990kbps is nice, the very fact of the matter is that the majority telephones default to LDAC 330kbps, requiring you to enter developer settings and drive the upper possibility.

Headphones with LDAC assist are exhausting to return by, and are sometimes accompanied by a excessive price ticket.

HWA Alliance’s LHDC and LLAC codecs

Huawei Logo 2020 1

Robert Triggs / Android Authority

LHDC is an acronym for low-latency and high-definition audio codec, and was developed by the Hello-Res Wi-fi Audio (HWA) Union and Savitech. Android 10 and up helps this codec as part of the Android Open Supply Undertaking (AOSP). It’s major profit: it offers thrice the info transmission allowed by SBC, and it helps a max bitrate of 900kbps with a max pattern fee of 96kHz. Huawei’s Mate 10 was the primary smartphone to assist this codec.

One other HWA codec: the low-latency audio codec (LLAC/LHDC LL) is a viable various to LHDC and boasts low-latency options, which is nice for cell players. Optimum latency charges are as little as 30 milliseconds, and it helps high-quality bitrates (400/600kbps) with a most pattern fee of 48kHz. LLAC was first supported by the Huawei P30.

Bluetooth LE Audio LC3 codec

The LC3 Bluetooth codec made a splash at CES 2020, and whereas we’re nonetheless ready on vital specifics we all know fairly a bit about this jack-of-all-trades codec. For one LC3 will ship help to the deaf and hard-of-hearing neighborhood by increasing Bluetooth performance: a single supply will be capable to stream to a number of Bluetooth gadgets. Which means Bluetooth-enabled listening to aids will be capable to stream audio (e.g. practice departure info) whereas conserving customers conscious of their environment.

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LC3 is a clear codec. Whole harmonic distortion minimization is proscribed by a telephone’s {hardware}, not by LC3.

In the same vein, LE Audio LC3 signifies that completely different broadcasts will be capable to transmit to a single pair of true wi-fi earbuds. Fairly than a single 160kbps stream, LC3 audio will break the stream up into 80kbps charges every. That is nice for those who and a pal are at a pub watching a neighborhood recreation: you should utilize the precise earbud to tune into your most popular announcer, whereas your mate can use the left earbud to tune into his favourite announcer.

Samsung scalable codec

Samsung Galaxy Buds Pro 10

Adam Molina / Android Authority

The primary-generation Samsung Galaxy Buds introduced with it the Samsung scalable codec. This capabilities equally to aptX adaptive, however is just suitable between Samsung gadgets (e.g. the Samsung Galaxy Buds Plus and Samsung Galaxy S20). The size adjusts from 88-512kbps) calable Codec prevents audio chopping by analyzing the radio frequency surroundings and adjusting the bitrate dynamically (from 88kbps to 512kbps). To get a complete record of supported Samsung gadgets, click on right here.

Associated: Samsung Galaxy Buds Professional overview

Do Bluetooth codecs really make a distinction?

The Shure Aonic 50 noise cancelling headphones worn by a woman using the Shure mobile app.

Lily Katz / Android Authority

Effectively, sure and no. If you happen to undergo from noise-induced listening to loss or are listening from a significantly noisy surroundings, it’s unlikely you’ll be capable to discern the variations between SBC, aptX, and AAC. That mentioned, there are extra advantages to high-quality codecs than sound high quality, specifically responsiveness. If you happen to’ve ever skipped a monitor by way of your headphones’ onboard controls solely to attend a second earlier than the following track really started taking part in, your system was in all probability streaming over SBC. This lag is much more noticeable in issues like video playback whereby late evening present hosts’ jokes are sullied by the audio-visual lag accompanying SBC streaming. Granted, there may be compensation inbuilt to maintain video and audio in sync. This preemptive calculation doesn’t utterly negate skips and hiccups, although.

In the end, this barrage of data is tough to maintain straight. To sum it up in a thought: aptX and aptX HD are Android customers’ selection codecs whereas iPhone customers ought to maintain to AAC-supported headphones. To proceed geeking out over Bluetooth codecs, take a look at our in-depth explainer.

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