Lossless audio (over bluetooth)

[eclipse01]

So i'm confused, I thought Lossless over bluetooth was impossible, but it was announced that the new Sonos "ACE" headphones will be able to pull this off.

how?

 

[arw]

Sonos Ace supports lossless audio over Bluetooth when connected to an Android device that includes Qualcomm Snapdragon Sound AptX for Lossless.

Lossless audio is not available when connected to an iOS device via Bluetooth.

Lossless audio requirements for Sonos Ace

You can listen to lossless audio on Sonos Ace over USB-C connections or over a Bluetooth connection with a supported Android device.

support.sonos.com

 

[mdedetrich]

The real bummer here is that no Apple devices have support for AptX (let alone AptX Hd, Aptx Lossless, Aptx Low Latency). iOS on the iphone never had these codes and macbook pro's at least had Aptx but they apparently removed it in Monterey (see https://gist.github.com/dvf/3771e58...malink_comment_id=4341403#gistcomment-4341403)

Its a shame, because afaik Apple does actually use Qualcomm SOC's for the modem/wifi/bluetooth so if correct its technically possible for them to support these codec's (and the decoder's for a lot of these are free to use if you are just using it as a decoder)

 

[Ben J.]

A little off-topic perhaps, but as a studio engineer (ret), I'd be more worried about the quality of the audio of the microscopic DACs and audio quality in general of these wireless devices than the level of compression of the data being sent to them.

 

[JCCL]

I use LDAC with my Sony XM5 using in my Surface Pro 8 using a driver. The difference is quite noticeable. Sucks that Apple doesn’t support LDAC or aptX.

 

[mdedetrich]

A little off-topic perhaps, but as a studio engineer (ret), I'd be more worried about the quality of the audio of the microscopic DACs and audio quality in general of these wireless devices than the level of compression of the data being sent to them.

This is only somewhat true, because the bitrate for these older bluetooth codec's is so low that even with "average/substandard" DAC's its still quite perceptible just by using a newer bluetooth codec with the exact same pair of headphones.

Also this isn't the 90's, the difference between an external high end DAC and the ones that are used in higher end wireless headsets is not as big as it was in the past. Unless you have a good set of wired headphones + dedicated amp (which is not the case for wireless headphones), the DAC chip inside the wireless headset in most cases is not going to make a meaningful difference.

Wireless headphones by nature of their physical design (especially if they have ANC) are not going to produce the same amount of audio quality as dedicated wired ones, irregardless of the DAC.

 

[SactoGuy18]

In order to get very high sound quality over Bluetooth, you need to have the Qualcomm AptX HD codec and a compatible headphone. Relatively few cellphones support AptX, though if Apple decides to extend their licensing deal with Qualcomm with the Snapdragon radio modem chip they should license AptX so it works with the successor to the H2 Bluetooth chip to get essentially CD quality sound over Bluetooth.

 

[seggy]

In order to get very high sound quality over Bluetooth, you need to have the Qualcomm AptX HD codec and a compatible headphone. Relatively few cellphones support AptX HD

Actually lots do and from quite a long time back, just not anything with a fruit logo on it

 

[seggy]

A little off-topic perhaps, but as a studio engineer (ret), I'd be more worried about the quality of the audio of the microscopic DACs and audio quality in general of these wireless devices than the level of compression of the data being sent to them.

The (ret) does explain things a bit in terms of the relevance of your post now - there's been significant advances where a tiny discrete can do everything an ultra high end dacamp did from 20 years ago, as long as it's driving something that doesn't require a ton of power - e.g. the small drivers in an earphone, which also have had significant development in the last couple of decades.

There are compromises of course, but not nearly as much as you would think. The actual hurdle isn't really the quality that each component is capable of, it's the potential signal mangling that goes on in the bluetooth audio chain of a modern earphone.

So however high a quality your hardware is capable of, if like in the case of all Apple devices and everything else that doesn't support AptX HD / Adaptive / LDAC, and you're trying to e.g. play back 44.1/16b lossless FLAC, what it will do is mangle that to 48/16 320kbit SBC (in optimum conditions) prior to slinging it to the earphones. (and in the case of pretty much all Bluetooth codecs you're looking at a 48khz change in either case to start with, and only LDAC to my knowledge can be forced into bit-perfect for 44.1/16) It's obviously not terrible in practice, but it's a tangibly lossy mangling of the audio in either case. LDAC in particular does away with that issue, so it delivers more of the original audio to the head/earphone to work with.

Then these days we get to ANC, and both the capability of the ANC and what it's tuned to do. This will have a further impact on audio quality.

You could argue that in a portable scenario you will never be able to discern the difference between lossy and lossless, and that's true if your earphones offer no isolation or are in a location where ANC with minimal passive isolation is actually useful. But that's kind of semantics if we're talking about the ultimate quality that can be delivered downstream - and in that respect, Apple handsets are bottom of the heap now.

 

[WeekendGearGuide]

Posted this on reddit many months ago, but always good to share the wealth of knowledge from my own personal experience with my personal experience with my own "Lossless" TWS Bluetooth Earbuds.

Cheers!

Bluetooth "Lossless" CD Quality Audio 101 (and why we aren't there...yet)​

After purchasing my Denon PerL Pro and HUAWEI FreeBuds Pro 3, I became very interested not only in how good their Voice Call Quality is, but also on their advertised "Lossless" Sound Quality that they both proudly claim in their marketing material, and wanted to share what I've learned and tried to add some reference links to support these findings. I know there are some Audiophiles here so please feel free to add more info or constructive corrections for all to learn from.

While an Earbud's acoustic hardware design and components used such as drivers, vents along with incorporation of smart software such as Masimo AAT plus the ability to fine tune the sound using multi-band EQ and Spatial Audio are all big contributors to an Earbuds Sound Quality, another big contributor would be the hi-res quality of the source material and the Bluetooth codec supported and used by both the Phone and Earbuds to maintain and reproduce the original source material hi-res data.

So the question is:

Does true "Lossless" Bluetooth Audio exist today?
Short answer: No


Long Answer with Context
--------------------------------------
In order to fully answer whether true "Lossless" Bluetooth Audio exists today, we need to answer the following questions below:

What is the minimum requirements for Lossless Audio?
The minimum requirement is to match CD Quality which has the following minimum specs:
- Sample Rate = 44.1kHz
- Depth = 16-bit
- Channels = 2 (Stereo)
- Bitrate = Sample Rate x Depth x # of Channels = 1411.2 kbps = 1.4112 Mbps
- Audio File Codec Format = Uncompressed PCM/WAV

By comparison, here is Hi-Res Lossless Audio max specs used by audio streaming services:
- Sample Rate = 192kHz
- Depth = 24-bit
- Channels = 2 (Stereo)
- Bitrate = Sample Rate x Depth x # of Channels = 9216 kbps = 9.216 Mbps
- Audio File Codec Format = Lossless Compression (FLAC or ALAC)

What are the most popular music streaming services that support Lossless Audio?
- Apple has developed its own lossless audio compression technology called Apple Lossless Audio Codec (ALAC). The entire Apple Music catalog is encoded using ALAC in resolutions ranging from 16-bit/44.1 kHz (CD Quality) up to 24-bit/192 kHz
- Amazon Music offers lossless audio in two quality ranges: HD and Ultra HD. HD tracks are 16-bit audio, with a minimum sample rate of 44.1 kHz (16/44.1 is also referred to as CD-quality), and an average bitrate of 850 kbps. Ultra HD tracks have a bit depth of 24 bits, with sample rates ranging from 44.1 kHz up to 192 kHz, and an average bitrate of 3730 kbps.

What is the best Bitrate supported by Bluetooth Specifications that may be able meet minimum Lossless Requirements?
- Fastest Theoretical Bluetooth Bitrate is 3Mbps specified in Bluetooth 2.x Specification
- Second fastest theoretical Bluetooth Bitrate is 2Mbps specified in Blueooth 5.x Specifications
- Note that Bluetooth HS (High Speed) first specified in Bluetooth 3.0 Spec using Alternate 802.11 MAC/PHY (eg. WiFi radio) to achieve theoretical speeds of up to 24Mbps, is not supported on any Bluetooth Headphones or TWS Earbuds.

Is Bluetooth 2.x with the fastest 3Mbps Theoretical Bitrates used by any Products today that market "Lossless" Bluetooth Audio?
- No

What Bluetooth Specification is used today by Products using Bluetooth Audio Codecs that market "Lossless" Bluetooth Audio?
- Bluetooth 5.3

What are the Bluetooth Audio Codecs that market "Lossless" Bluetooth Audio?
- HUAWEI's L2HC 3.0 codec with a bitrate of up to 1.5Mbps
- Qualcomm's aptX Lossless codec with a bitrate of up to 1.2Mbps and depth and sample rate of 16-bit 44.1kHz

Why is L2HC 3.0 and aptX Lossless codecs not truly "Lossless"?
- Any claims of meeting or exceeding the minimum Lossless bitrate of 1.4112 Mbps is currently impossible on products marketing "Lossless" audio using Bluetooth 5.3. Even though Bluetooth 5.3 specifies a theoretical maximum bitrate of 2 Mbps, actual bitrate in absolute best conditions max out at around 1.3Mbps. Typical real world bitrates expected to be worse in a typically congested 2.4GHz environment. Thus, L2HC 3.0 will not be able to practically achieve true Lossless using the latest Bluetooth 5.3 specification and with its limitations.
- aptX Lossless with a bitrate of 1.2Mbps, claims to use a Lossless Compression technique that is similar to what FLAC and ALAC use, but is also limited by the Bluetooth 5.3 2Mbps max theoretical bitrate and RF and interference challenges inherent in a 2.4GHz environment.
SUMMARY: Current 2Mbps theoretical maximum bitrate limitations in Bluetooth 5.x specification combined with real world challenges in RF and interference from other 2.4GHz devices prevent a true Lossless wireless experience on being fully achieved.

What's needed in future Bluetooth Specifications to achieve true Bluetooth Lossless Audio?
- Higher bitrate support of at least 12Mbps to provide enough overhead to support Hi-Res Lossless Audio of 24-bit * 192kHz * 2 channels @ 9.216 Mbps bitrate, already supported on many streaming services today.
- How this will be accomplished while maintaining low power consumption, over reasonable distance and still mitigating interference in the 2.4GHz ISM frequency (or maybe other frequency) will be challenging.

OK, I don't care if L2HC 3.0 and aptX Lossless are not truly "Lossless", they are the best codecs right now. What TWS Earbuds, Headphones and Phones support this?
- L2HC 3.0 is supported on:
* HUAWEI FreeBuds Pro 3 TWS Earbuds (China version only)
* HUAWEI Mate 60 series
* HUAWEI Mate X5
- aptX Lossless is supported on the following devices (and many others listed on aptX):
* Denon PerL Pro
* Bose QuietComfort Ultra Earbuds
* Bose QuietComfort Ultra Headphones
* SOUNDPEATS Air4
* Sony Xperia 5 IV
* ASUS ROG Phone 7
* ASUS Zenphone 10

 

[Ralfi]

Thanks for breaking it down.

HD tracks are 16-bit audio, with a minimum sample rate of 44.1 kHz (16/44.1 is also referred to as CD-quality), and an average bitrate of 850 kbps

Am I reading this correct? Shouldn’t the average bitrate be above 1411.2kbps?

Why is the average below that minimum for 16/44.1 content? Mono tracks?

 

[arw]

Am I reading this correct? Shouldn’t the average bitrate be above 1411.2kbps?
Why is the average below that minimum for 16/44.1 content? Mono tracks?

As illustrated by @WeekendGearGuide, 1411.2 kbps is uncompressed 16/44.1 audio (PCM/WAV).
Similar to a zip or rar archive, you can losslessly compress audio.
FLAC and ALAC can save up to 30-50% of the original file size depending on the complexity of the songs.
While still being bit-perfect to the original WAV, the resulting bitrate (a.e. 850 kbps) reflects the compression.
To save bandwith and storage on the end user side, lossless files are mostly distributed as FLAC or ALAC.
Pure WAV files also lack proper metadata and artwork.

And yes, a 16/44.1 mono WAV track has a bitrate of 706 kbps (exactly half of 1411 kbps).

 

[SactoGuy18]

I still hope that Apple would seriously look at switching to a new Bluetooth chip that will support at least AptX HD on the iPhone and iPad. While not completely lossless sound quality, AptX HD is capable of much better sound quality than what is available now with Apple devices. Why AptX? Mostly because it's more tolerant of noisy signal conditions than Sony's LDAC codec.

 

[kitKAC]

I still hope that Apple would seriously look at switching to a new Bluetooth chip that will support at least AptX HD on the iPhone and iPad. While not completely lossless sound quality, AptX HD is capable of much better sound quality than what is available now with Apple devices. Why AptX? Mostly because it's more tolerant of noisy signal conditions than Sony's LDAC codec.

Are any of those CODECs free to use? Because if they're not...

 

[kitKAC]

Has anyone seen anything online about how this works?

 

[SactoGuy18]

Are any of those CODECs free to use? Because if they're not...

Because Apple is arguably the largest user of the Qualcomm 5G modems in the world, they could easily negotiate a really cheap deal for a Bluetooth chip that supports both AptX and AptX HD.

 

[Howard2k]

Has anyone seen anything online about how this works?

View attachment 2386236

Yes, here:

Apple Explains Why Only USB-C AirPods Pro Support Lossless Audio With Vision Pro

In a video interview with Brian Tong, Apple's VP of Sensing and Connectivity Ron Huang explained why only the updated second-generation AirPods...

www.macrumors.com