Bluetooth codecs can be found on most Bluetooth headphones and earbuds. They support AAC/or aptX, in addition to the standard SBC codec. While these codecs are different in the way they compress the audio sent from your smartphone to your headphones, there is one thing they all have in common: They can only handle 16 bits. That’s enough resolution for most kinds of audio, and many experts believe it’s enough, period.
Not everyone is convinced that hi-res audio actually sounds better, but if you’ve got access to a source of lossless, 24-bit music, whether from your own personal files or from a streaming music service, you may want to consider buying a set of buds or headphones that can support a Bluetooth codec designed to deliver that extra level of detail. LDAC and aptX HD (the most commonly used 24-bit compatible codecs) are also available.
Qualcomm is responsible for the development of chips for mobile devices. LDAC was created by Sony, and the company makes extensive use of it on its products.
Which codec is best? That depends on a lot of factors, so let’s start at the beginning.
These codecs are not supported by Apple at the moment. The 16-bit AAC codec is the only one that Apple supports if you have an iPhone or iPad. On some older Macs running macOS versions earlier than Catalina, it’s possible — with some work — to get aptX support, but even then, you’re still limited to 16-bit audio.
Google introduced LDAC and AptX HD in Android 8.0. They are available to any Android smartphone manufacturer. If your phone is on Android 8.0 or higher (and as long as your phone’s manufacturer hasn’t intentionally disabled one or both), you should be able to use them with a compatible set of earbuds or headphones.
AptX Adaptive is the newest of the three codecs, and while it also runs on Android devices, it’s not built into the Android operating system. Only Android phones that use Qualcomm’s audio chipsets can support aptX Adaptive. Still, if we’re talking about Android phones that have been released since about 2020, aptX Adaptive support is very good across all of the major brands and many smaller ones — with one very notable exception: No Google Pixel phones currently support aptX Adaptive.
Any wireless headphones or earbuds that support aptX Adaptive must also use Qualcomm’s chips. From This places aptX Adaptive at a slight disadvantage in terms of compatibility and availability.
AptX HD has limitations too, but in this case, it’s strictly on the headphones side of the equation. For reasons we’ll get into shortly, aptX HD is primarily used for wireless headphones, not wireless earbuds. There are some exceptions — like the Bowers & Wilkins PI7 — but they’re very rare. If you’re shopping for wireless earbuds, they will most likely offer aptX or aptX Adaptive, but not aptX HD.
LDAC is free from any restrictions. It works on headphones and earbuds, and even though the codec is owned and licensed by Sony, a manufacturer doesn’t need to use Sony’s chips to add LDAC support to their products — it can be implemented using software on a variety of processing platforms. LDAC is the obvious winner for compatibility.
It is not the same story with availability. LDAC is not a common choice for many manufacturers. The list includes 1More and Soundpeats Soundcore, Soundpeats and Shure. During this time, aptX HD has been used more than 30 times by headphone makers, while aptX Adaptive is used by even more companies if you include headphones and earbuds.
In theory, with LDAC’s ability to run on headphones and earbuds, and its software-based implementation, it should be the most widely used of the 24-bit codecs. However, that isn’t how it has played out — at least so far.
Winner: aptX adaptive
Sound quality can be subjective and can be affected by many factors. For instance, if you’re using a set of budget headphones to listen to compressed music, your choice of Bluetooth codec probably won’t make any difference to what you’re hearing. Because of this, we’ll avoid making any judgment calls on which codec sounds best. Instead, let’s take a look at each codec’s potential based on its technology and specifications.
A codec is used for wireless audio transmission. It encodes the audio at a specified resolution (bit depth), and a particular sample frequency (kHz). These numbers are generally higher than the ones you see, so the quality of your audio will be better.
AptX HD works at 24 bits and 48kHz. This should be sufficient to transmit high-quality audio and capture it at 24 bits. However, in order to technically be considered “hi-res,” a codec needs to support sample frequencies above 48kHz. LDAC and aptX Adaptive are both compatible with this requirement, offering a 24-bit/96kHz top quality. Whether you’ll be able to hear that difference or not is highly debatable, but if you’re listening to 24-bit/96kHz or better audio and want to preserve as much of that signal as possible, LDAC and aptX Adaptive are the way to go.
Winner: LDAC and aptX adaptive are tied in a two-way partnership
I know you’re yelling at me, geeks. Resolution and sample frequency are important for audio quality when dealing with high-resolution audio files. But Bluetooth can be a problem. You need to understand how a codec responds under extremely variable wireless conditions.
We’re talking about bit rate, or the amount of data a codec uses to send information across a Bluetooth connection. The bit rate determines how much information can be sent and the quality of the sound.
Some codecs have fixed bit rates, which means that they can’t react to changes in the quality of a wireless link. AptX HD, a codec with fixed bit rates, requires constant speeds of 576Kbps for 48kHz sampling frequencies. If your connection is capable of handling this speed, AptX HD should deliver full quality. But if the quality of your connection drops below that speed, which can happen when you’re too far from your phone or there’s a lot of wireless interference, the audio will start to break up. It’s an all-or-nothing proposition.
LDAC and aptX Adaptive are scalable codecs — they can adjust the amount of bandwidth they use in response to your Bluetooth connection. LDAC moves between three speeds: 330Kbps (with no intermediate steps), 660Kbps (with intermediate steps) and 990Kbps. aptX Adaptive dynamically adjusts its speed in 10Kbps increments.
It’s rare that a Bluetooth connection can be maintained at LDAC’s top speed of 990Kbps — this really requires ideal conditions. LDAC will run at 660 unless you force your phone into using the 990Kbps speed. This is possible with the optional developer settings.
AptX Adaptive’s ability to smoothly scale instead of stepping in such large increments, and its lower overall speed requirements means it will be able to connect at its top quality more of the time while presenting a far less noticeable transition when it needs to ramp its speed downward.
On paper, LDAC’s 990Kbps bitrate is clearly the best of the three, with almost double the amount of data transmitted per second than aptX HD and almost 50% more than aptX Adaptive. However, there’s not much point in being able to achieve 990Kbps if conditions almost never allow it to happen. And as we’ll see in a moment, what you do with that bit rate is just as important.
Winner: aptX adaptive
As the newest of the three codecs, you’d expect aptX Adaptive to be the most efficient (the ability to maintain the greatest amount of detail with the least amount of transmitted data), and it is. In some ways, it’s not even a fair comparison. Not only is aptX Adaptive newer in terms of its code, it only runs on Qualcomm’s chips, effectively giving it a home-field advantage.
Qualcomm claims that aptX Adaptive delivers the same audio quality (576Kbps) as aptX HD at just 420Kbps. And though Qualcomm makes no direct claims about LDAC, we know that aptX Adaptive can deliver the same 24-bit/96kHz mode as LDAC’s 990Kbps at just 660Kbps.
We haven’t been able to find a scientific set of measurements that clearly shows how LDAC and aptX Adaptive perform at their respective top bit rates, but it’s worth repeating: If a codec can’t deliver its top level of quality without a very hard-to-reach bit rate, does it really matter?
Winner: aptX adaptive
Latency is the time that it takes to hear a sound after it’s been created by your device. For regular music listening, latency doesn’t matter much, but if you’re gaming or watching any kind of video with dialogue, you want that time to be as short as possible. Gaming community consensus is that any lower than 32ms is fast enough for a comparable gaming experience to a wired headset.
Bluetooth audio latency is affected by many factors. However, codecs are an important component. AptX HD’s reported latency ranges from 200ms up to 300ms. LDAC can have similar long lag times.
AptX Adaptive, on the other hand, can adjust its performance based on the kind of audio you’re streaming. If it detects that you’re gaming, making a phone call, or doing anything else that might require low latency over high resolution, it can operate as low as 80ms.
That’s enough to earn it a win in the latency category, but it might get even better. Qualcomm says that if you’re using a phone and wireless headphones that have both been certified under its Snapdragon Sound program, latency as low as 40ms — the same performance as its aptX Low Latency codec — could be possible.
Winner: aptX adaptive
One thing we’ll probably never get enough of when it comes to wireless headphones and earbuds is battery life. It’s not something we enjoy doing, so it’s better to charge them less often.
This presents a problem for LDAC. LDAC running on headphones and earbuds can lead to a dramatic reduction in playtime. On Anker Soundcore’s recently released Liberty 4 earbuds, engaging the LDAC codec drops their playtime from nine hours per charge to just six hours.
The aptX family codecs have always been more efficient that its rivals. This applies to both aptX HD (and aptX Adaptive). Low power consumption isn’t a key feature of Adaptive, but Qualcomm says it uses less power to deliver the same performance as aptX HD. These efficiencies will likely get better over time thanks to improvements in Qualcomm’s chips.
Winner: aptX Adaptive
In some ways, this wasn’t a fair comparison. As the newest of the three codecs, AptX Adaptive has several advantages that LDAC and aptX HD simply can’t match. It works on earbuds and headphones alike, it doesn’t require a near-perfect wireless connection to deliver 24-bit/96kHz audio, and it can respond to ever-changing conditions quickly and seamlessly so you can always hear your tunes. It doesn’t require a lot of extra power, and while it may not be standard equipment within the Android operating system, you can find tons of smartphones and wireless audio devices that support it.
Our overall winner is: aptX Adaptive
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