LDAC, LHDC, AptX Adaptive, AptX Lossless, these are the 4 main high res Bluetooth codecs. And I have vigorously tested all of them out over the last few years, with tons of true wireless earbuds, streaming services and devices. And what I’ve learned is that it’s a bit of a mess to get them to actually work properly. But if you can’t get them to work properly, is it even worth the sound quality improvement that you get? Well, I’m gonna answer that question by the end of this post, but first let’s talk about the different codecs that are out there.
High res Bluetooth codecs and bitrate
I’m just covering the main ones here. So there’s SBC, AAC, AptX, AptX Adaptive, LDAC, LHDC, and AptX Adaptive Lossless. And they all have a varying speed of data transferred, which is represented as kilobits per second. This also goes by the name bitrate.
AAC has the lowest at 256 kilobits per second, AptX Lossless – the highest at 1200 kilobits per second. Some sources will state it’s over 1000 kilobits per second. This is actually very tricky information to find out for some reason. And this trend of not knowing completely what you’re actually getting will continue throughout this post.
So you’re getting over four times the amount of transfer speed going from AAC to AptX Lossless. So does that mean you’re getting four times the audio quality? Definitely not.
High res Bluetooth codecs and bit depth
Now there’s also bit depth, which represents the dynamic range of your audio. Basically, the higher the bit depth, the more detail you can capture in sound. This is particularly relevant for producers or anyone mixing and mastering tracks. Generally, a bit depth of at least 24-bit is considered more than enough for creating music or high-quality audio.
You can also get options like 16-bit and 32-bit. I like to think of it as similar to filming in 4K and then exporting in 1080p – your video would likely look better than if you’d filmed directly in 1080p. (Maybe not the perfect example, but you get the idea. 😉 )
Most codecs here stick to 16-bit, though. LHDC can reach 24-bit, while LDAC can go up to 32-bit.
Then there’s AptX Lossless, which only offers 16-bit but has the highest bitrate. So, what’s going on there?
High res Bluetooth codecs and sample rate
Well, the third component to this confusing mix of numbers is sample rate, which is represented by kilohertz. So the sample rate is a number of times a file is sampled each second in the audio stream.
This goes as high as 192 kilohertz for LHDC and the lowest 44.1 kilohertz for AAC and AptX Lossless. Generally for audio to be regarded as high-res, you need at least 48 kilohertz. So that’s why AptX Lossless isn’t considered high-res, it’s considered lossless.
Only LDAC, LHDC, and AptX Adaptive High-res get the high-res badge.
Bit rate calculations
With all three numbers for the high res Bluetooth codecs, you can calculate the actual bitrate. Let’s try AptX Lossless.
Take 16-bit audio, multiply by 44.1, then by two. That gives you 1,411 kilobits per second, considered CD quality. This has been the standard since CDs were first developed, as it was thought to be good enough for most people’s hearing.
But wait a sec, isn’t the maximum bit rate of AptX Lossless 1,200 kilobits per second, not 1,411? That’s right, so I actually don’t know why they call it AptX Lossless because the idea of it is that it’s supposed to stream at CD quality without losing anything. But you’re losing 211 kilobits per second there. I’m no expert, but that doesn’t seem like Lossless.
Let’s do another calculation. If you take 24-bit audio, multiply it by 192, and then by two, you end up with 9,216 kilobits per second. Now, compare that to LHDC, which caps out at a maximum bitrate of 1,000 kilobits per second. So, there’s a bit of a quality drop there.
This raises a question for me: is it better to stream using AptX Lossless, which gives almost CD-quality audio, or to go for a higher kilohertz range at a lower bit rate? Honestly, I couldn’t find much concrete information on this. All I can really go off of is my own listening experience with different devices, codecs, and streaming services.
If you’re not totally following the numbers here, don’t worry. I don’t entirely understand it all myself! But before diving into that, we should talk about the different streaming services out there – because, unfortunately, it only gets more confusing from here.
Streaming services
You’ve all probably heard of Spotify. It streams classic MP3 files at 320 kilobits per second, while a service like Apple Music streams in 24-bit, 192 kilohertz. This setup works well on an iPhone – but only if you’re using a wired connection, since iPhones rely on the AAC codec with a maximum bitrate of 256 kilobits per second over Bluetooth. On macOS, it gets trickier because you might need an extension (like the Lossless Switcher) or to adjust settings in Audio MIDI to ensure it streams at 24-bit, 192 kilohertz.
And just to clarify: that’s 192 kilohertz, not 196. I know, a lot of numbers – bear with me! 🙂 Some Android devices support LHDC, which can actually output at 24-bit, 192 kilohertz.
If you use Apple Music on Android, though, it downscales to 48 kilohertz, a limitation of the Android OS. Some apps handle it better than others, while others need workarounds. Services like Amazon HD, Deezer, and Qobuz have their own quirks – often downsampling unless you install extensions to keep the higher quality. But it seems Tidal is the only app that can stream lossless without extra steps.
The only downside with Tidal and many streaming services is that not all songs are available at the maximum 24-bit, 192 kilohertz. Only a handful of tracks stream at that level, but most still play at CD quality (16-bit, 44.1 kilohertz), which is perfectly fine.
My experience
Now let’s dive into my listening experience with different codecs.
Starting with Android: if you go from SBC, which is the lowest quality codec, to aptX, you’ll notice a slight bump in sound quality – mainly a bit more detailed treble and a touch of richer bass. I’d say regular aptX on Android is roughly on par with AAC on iOS.
On Android, though, AAC can actually sound worse than SBC, depending on the device. There are just so many different Android models, so performance varies. Generally, AAC works best on Apple devices, just like aptX tends to work better on Android.
If you move up from regular aptX or AAC to high-res codecs like LDAC, LHDC, aptX Adaptive High Res, or aptX Lossless, you’ll notice a small improvement in sound quality. But honestly, it’s so subtle that I sometimes wonder if it’s just placebo.
Think of it this way: imagine spending hundreds on earbuds with high-res audio or aptX Lossless support. You’ve got your high-res audio files or a streaming service boasting 24-bit, 192-kilohertz quality – all those big numbers staring at you. It’s easy to convince yourself it sounds better. But if you put me through a blind test comparing AAC or aptX to one of these high-res codecs, I doubt I’d pick the right one more than 30% of the time.
Now, my hearing isn’t perfect, but I’ve been reviewing true wireless earbuds for the past four years, so I’m listening to audio devices constantly. Maybe if you’re into mixing and mastering, you’d score over 50% on that same test, but I’m honestly not sure.
The best sound? Whatever works for you
All that said, I get why people want to know they’re streaming at the highest possible quality over Bluetooth. And even if it’s just a placebo, if it makes the listening experience better, who’s to say it doesn’t count? For me, I prioritize convenience, which is why my go-to setup is my iPhone 15 Pro with Spotify. I’ve been on Spotify for over 10 years, and the sound quality is great.
In the end, what really determines the best audio quality over Bluetooth is the earbuds themselves and how they’re tuned. And, of course, you can always adjust the EQ to suit your own preferences.
Thanks for reading, folks! Be sure to check out my latest reviews on the best headphones for running and those perfect for ASMR listening. Happy listening!