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No, it definitely isn't. Why is audio quality so much worse when I connect my headphones as headset instead of as audio-sink (even when I'm not speaking). Why i

No, it definitely isn't. Why is audio quality so much worse when I connect my headphones as headset instead of as audio-sink (even when I'm not speaking). Why is it so hard to connect two audio sinks to one source? Why is the experience of using the same sink on multiple devices still not smooth?

andix 6y ago
I also don't get why this was not fixed yet. There is clearly the need for high quality Bluetooth headsets. Two sinks to one source works well for some devices. But this is more an edge case for most people. I also have the feeling, that Apple AirPods have a better quality if you connect them to an iPhone, then any other Bluetooth headsets. Do they use a proprietary Handsfree profile?
- rusk 6y ago
  My understanding is that the AirPods and iphone have a high quality codec that isn’t widely supported yet ...
  - willtim 6y ago
    My understanding is that music gets decompressed on the Apple headphones, the original AAC stream is sent over the wire. Most Bluetooth headphones will just effectively transcode the audio, such that for example AAC gets decompressed then recompressed into AptX/LDAC. For music listening, it's completely suboptimal. I use FLAC sources for my Sony headphones which makes them very listenable (along with copious EQ to tame the +5db excess bass). Bluetooth headphones have a lot of room for improvement.
    - em500 6y ago
      > My understanding is that music gets decompressed on the Apple headphones, the original AAC stream is sent over the wire. That's claimed at many places, but this one claims the opposite: https://habr.com/en/post/456182/ https://habr.com/en/post/456182/, that everything gets (re-)compressed into AAC on the sending device before sending it to the Airpods, in order to mux other audio events. In principle, with end-to-end Apple hardware, they could send multiple streams and leave the muxing to the Airpods, but I don't think anyone has conclusively shown if this is actually done.
      - deleted 6y ago
        [deleted]
      - marcan_42 6y ago
        If there's one thing I've learned about technical claims about Apple hardware, it's that they are not to be believed unless they come straight from Apple in a precise and unambiguous statement, or from a reverse engineer/hacker who has looked at the code/protocols. The reality distortion field is just as strong as always when it comes to technical details too. People will make random things up to prove that Apple is different or (more) special.
    - marcan_42 6y ago
      Claims of poor Bluetooth audio quality generally fall into the following categories: * Bad source settings/implementation (i.e. bitrate too low) * Bad sink implementation/EQ/DAC * The HSP issue referenced by OP (where you can't have both HQ audio and use the mic) * FUD by patented codec authors The reality is that even the basic royalty free Bluetooth SBC codec is perfectly fine, and sounds transparent at high bitrate settings, which decent sources should be using and all sinks are required to support. Transcoding doesn't make much of a difference either. It's a poor codec, but the bitrate is high enough that it doesn't matter. You can ABX test it yourself if you're so inclined, purely in software, with high quality wired audio hardware. I have. You'll see the codec isn't the problem. So when your Bluetooth device sounds better wired than wireless, or works better with AptX or some other patented nonsense codec - most likely the problem is careless software/firmware (or outright crippling to push patent licenses), not the spec being bad. (I say this as someone who was gotten into flamewars over the quality of ffmpeg's AAC implementation and found bugs in the Opus reference encoder; I can tell when audio quality drops)
      - willtim 6y ago
        > Transcoding doesn't make much of a difference either. I respectfully disagree. Transcoding does make an audible difference, at the bitrates typically used, and should have no place in "high fidelity" audio. My issue with these Bluetooth codecs is that they are not used at the sources and so will always be used in practice for transcoding.
        marcan_42 6y ago
        Have you ABX tested an SBC transcode at the maximum bitpool settings vs the original? Because I have, and I couldn't tell the difference. The "transcoding is bad" story is about low quality settings, archival, and/or bad encoders. E.g. don't do repeated transcodes with the ffmpeg AAC encoder, not even at 320kbps. But one final transcode with SBC for over-the-air delivery at the max allowed bitrate? That's totally fine, especially for typical Bluetooth use cases (listening on the go, casual headphones, etc).
        6y ago
amq 6y ago
Seems like this should be improved with Bluetooth 5.2 and LE Audio.
modeless 6y ago
And why does latency compensation still not work properly? For real time stuff like games or video chat it's tough to compensate for latency, but when watching a prerecorded video there's no excuse. Video and audio should never be out of sync, and yet I find they usually still are.
Cthulhu_ 6y ago
I guess because it switches to a mode that favors latency over sound quality? I tried using bluetooth headphones on a digital drumkit once, which went about as well as you'd expect. (mind you there was a laptop in between as well)
- slykar 6y ago
  It somehow works with dedicated USB dongles that are size of a penny. Look at Jabra Evolve 65T. From my perspective as a customer it's an issue with Bluetooth standard, not hardware. The latency problems are somehow solved when using USB adapters, so why can't we embed those adapters in our devices?
  - rusk 6y ago
    Because all the switches that would allow you to tweak this are all safely locked in a black box, wrapped in a committee and sealed with an NDA. The problem with Bluetooth is the encumbrance of all the IP protection that surrounds it.
jankotek 6y ago
Headset voice has to squeeze over GSM voice channel, that is 9.6kbps. I had pretty smooth experience with using Pulse with multiple sinks/sources, maybe look into doc. Only problem I had was latency sync while multiple sinks play together.
lol768 6y ago
The headset profile is the bane of my existence. I have zero interest in using my wireless headphones as a headset, ever. And yet, software will randomly manage to trigger it and kick me off of the A2DP profile. Microsoft Teams is the worst at this. It completely ignores my system audio preferences (which were painstakingly configured to use the expensive microphone as an input, not the wireless headphones) and tries to use the headphones, which switches the profile to headset and ruins the audio quality for the remainder of the call. Bluetooth is far from OK for audio.
cybwraith 6y ago
The fact that high quality simultaneous audio input/output isn't possible is a big negative for BT that I just can't believe hasn't been addressed yet.

andix 6y ago

I also don't get why this was not fixed yet. There is clearly the need for high quality Bluetooth headsets. Two sinks to one source works well for some devices. But this is more an edge case for most people. I also have the feeling, that Apple AirPods have a better quality if you connect them to an iPhone, then any other Bluetooth headsets. Do they use a proprietary Handsfree profile?

rusk 6y ago
My understanding is that the AirPods and iphone have a high quality codec that isn’t widely supported yet ...
- willtim 6y ago
  My understanding is that music gets decompressed on the Apple headphones, the original AAC stream is sent over the wire. Most Bluetooth headphones will just effectively transcode the audio, such that for example AAC gets decompressed then recompressed into AptX/LDAC. For music listening, it's completely suboptimal. I use FLAC sources for my Sony headphones which makes them very listenable (along with copious EQ to tame the +5db excess bass). Bluetooth headphones have a lot of room for improvement.
  - em500 6y ago
    > My understanding is that music gets decompressed on the Apple headphones, the original AAC stream is sent over the wire. That's claimed at many places, but this one claims the opposite: https://habr.com/en/post/456182/ https://habr.com/en/post/456182/, that everything gets (re-)compressed into AAC on the sending device before sending it to the Airpods, in order to mux other audio events. In principle, with end-to-end Apple hardware, they could send multiple streams and leave the muxing to the Airpods, but I don't think anyone has conclusively shown if this is actually done.
    - deleted 6y ago
      [deleted]
    - marcan_42 6y ago
      If there's one thing I've learned about technical claims about Apple hardware, it's that they are not to be believed unless they come straight from Apple in a precise and unambiguous statement, or from a reverse engineer/hacker who has looked at the code/protocols. The reality distortion field is just as strong as always when it comes to technical details too. People will make random things up to prove that Apple is different or (more) special.
  - marcan_42 6y ago
    Claims of poor Bluetooth audio quality generally fall into the following categories: * Bad source settings/implementation (i.e. bitrate too low) * Bad sink implementation/EQ/DAC * The HSP issue referenced by OP (where you can't have both HQ audio and use the mic) * FUD by patented codec authors The reality is that even the basic royalty free Bluetooth SBC codec is perfectly fine, and sounds transparent at high bitrate settings, which decent sources should be using and all sinks are required to support. Transcoding doesn't make much of a difference either. It's a poor codec, but the bitrate is high enough that it doesn't matter. You can ABX test it yourself if you're so inclined, purely in software, with high quality wired audio hardware. I have. You'll see the codec isn't the problem. So when your Bluetooth device sounds better wired than wireless, or works better with AptX or some other patented nonsense codec - most likely the problem is careless software/firmware (or outright crippling to push patent licenses), not the spec being bad. (I say this as someone who was gotten into flamewars over the quality of ffmpeg's AAC implementation and found bugs in the Opus reference encoder; I can tell when audio quality drops)
    - willtim 6y ago
      > Transcoding doesn't make much of a difference either. I respectfully disagree. Transcoding does make an audible difference, at the bitrates typically used, and should have no place in "high fidelity" audio. My issue with these Bluetooth codecs is that they are not used at the sources and so will always be used in practice for transcoding.
      - marcan_42 6y ago
        Have you ABX tested an SBC transcode at the maximum bitpool settings vs the original? Because I have, and I couldn't tell the difference. The "transcoding is bad" story is about low quality settings, archival, and/or bad encoders. E.g. don't do repeated transcodes with the ffmpeg AAC encoder, not even at 320kbps. But one final transcode with SBC for over-the-air delivery at the max allowed bitrate? That's totally fine, especially for typical Bluetooth use cases (listening on the go, casual headphones, etc).
        6y ago

amq 6y ago

Seems like this should be improved with Bluetooth 5.2 and LE Audio.

modeless 6y ago

And why does latency compensation still not work properly? For real time stuff like games or video chat it's tough to compensate for latency, but when watching a prerecorded video there's no excuse. Video and audio should never be out of sync, and yet I find they usually still are.

Cthulhu_ 6y ago

I guess because it switches to a mode that favors latency over sound quality? I tried using bluetooth headphones on a digital drumkit once, which went about as well as you'd expect. (mind you there was a laptop in between as well)

slykar 6y ago
It somehow works with dedicated USB dongles that are size of a penny. Look at Jabra Evolve 65T. From my perspective as a customer it's an issue with Bluetooth standard, not hardware. The latency problems are somehow solved when using USB adapters, so why can't we embed those adapters in our devices?
- rusk 6y ago
  Because all the switches that would allow you to tweak this are all safely locked in a black box, wrapped in a committee and sealed with an NDA. The problem with Bluetooth is the encumbrance of all the IP protection that surrounds it.

jankotek 6y ago

Headset voice has to squeeze over GSM voice channel, that is 9.6kbps. I had pretty smooth experience with using Pulse with multiple sinks/sources, maybe look into doc. Only problem I had was latency sync while multiple sinks play together.

lol768 6y ago

The headset profile is the bane of my existence. I have zero interest in using my wireless headphones as a headset, ever. And yet, software will randomly manage to trigger it and kick me off of the A2DP profile. Microsoft Teams is the worst at this. It completely ignores my system audio preferences (which were painstakingly configured to use the expensive microphone as an input, not the wireless headphones) and tries to use the headphones, which switches the profile to headset and ruins the audio quality for the remainder of the call. Bluetooth is far from OK for audio.

cybwraith 6y ago

The fact that high quality simultaneous audio input/output isn't possible is a big negative for BT that I just can't believe hasn't been addressed yet.