this post was submitted on 17 Jul 2023
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For context, LDAC is one of the few wireless audio codecs stamped Hi-Res by the Japan Audio Society and its encoder is open source since Android 8, so you can see just how long Windows is sleeping on this. I'm excited about the incoming next gen called LC3plus, my next pair is definitely gonna have that.

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[–] [email protected] 9 points 1 year ago (8 children)

Shame about headsets though - has anyone been able to get the mic to work without the audio quality dropping to trash? It is a shame to have to pick between good quality audio and the ability to use your mic.

[–] [email protected] 22 points 1 year ago* (last edited 1 year ago) (1 children)

It's because all the good codecs (aptX, LDAC, even SBC) all operate over the A2DP Bluetooth profile, meaning your computer's Bluetooth adapter is running in a particlar mode called A2DP. Unfortunately, A2DP is unidirectional, (ie, not Duplex) it doesn't support sending audio to headphones and receiving audio from the mic at the same time, due to bandwidth limitations. So when you open Zoom or Teams or something that needs to access your mic, your Bluetooth adapter switches to a different mode like HSP (Handset Profile) and HFP (Hands Free Profile). These profiles do support duplex connection to the mic and headphones, but don't have fancy high definition codecs. They are designed to be very low bitrate. That's why you encounter such a big audio quality difference when it switches.

Note, having said that, pipewire on Linux does support some fancy faststream duplex modes that operate on A2DP, outside the constraints of what I explained above. Eg, it gives me the option to enable AptX-LL with faststream, that passes the mic through using whatever little leftover bandwith is on the connection. This doesn't work with heavier codecs like AptX-HD. I think Android does something similar, that is why you don't notice the profile swapping behaviour as badly on Android.

[–] [email protected] 2 points 1 year ago

A2DP itself does support bidi, faststream is a A2DP BIDI profile (it's SBC, it's bad because of really bad bitrate constraints for some reason though) AptX-HD actually support aptx-ll but I find most devices just bug out when you try it. opus also supports bidi on pw.

bandwidth limtations are not an issue with bluetooth itself, you can reliably maintain 300-600kbps, which is more then enough for good quality bidirectional audio. even when using asynchronous modes, you still usually have enough bitrate for audio that would be considered fine.

im not sure why it's not more popular in modern devices, IIRC all the patents on the subject have ended, could be a limitation of low end radios

[–] [email protected] 5 points 1 year ago

I don't think there are any hifi headset profiles, AFAIK.

[–] [email protected] 3 points 1 year ago (1 children)

I think that might be the codecs' fault. At least for me, my headphones sound terrible in headset mode on all the devices I've tried, regardless of whether they're running Linux, MacOS, iOS, or Android.

[–] [email protected] 3 points 1 year ago (1 children)

It's the profile, not the codec. The codec just defines how the audio is compressed, the profile defines all the parameters around that like duplex for microphones.

A2DP is the profile used for music by everything, HFP is the profile that is used for calling by most things nowadays.

[–] [email protected] 3 points 1 year ago

TIL! Thanks for the clarification.

[–] [email protected] 3 points 1 year ago* (last edited 1 year ago)

I feel you there. Personally I just use the earbuds as output and the integrated laptop mic as input. Bluetooth really just doesn't shine in that regard. However if you're on Desktop and want everything to happen on a headset, not earbuds x wired stand mic, you should look into things like HyperX Cloud 2 Wireless that employ a USB dongle instead.

[–] [email protected] 3 points 1 year ago

And it looks (for me) like on android it just works, so it should be possible… Or maybe it's just seamlessly switching shit-quality with mic and good quality without? And I didn't notice during gsm calls?

For sure it sucks on windows too, but well - anything bt-related on windows works just bad…

[–] [email protected] 2 points 1 year ago (1 children)

I ended up buying JBL Quantum TWS in-ears because they also include a USB-C dongle that speaks their own protocol which allows lowlatency duplex audio. Perfect for audio calls and even gaming. Plus, I don't need to pair them with every device, I can just bring the dongle. (They can also be paired with Bluetooth and you can switch between dongle and BT whenever you want.)

[–] [email protected] 2 points 1 year ago (1 children)

This is interesting. So these have the "non BT 2.4Ghz" protocol that you generally find in the huge wireless gaming headset?

Ive been looking for a wireless headset that has the low duplex latency of wireless gaming headset, but in a smaller package. Something like the "Microsoft Modern Wireless Headset" but with 2.4Ghz non BT. And I couldn't find yet something like this.

[–] [email protected] 2 points 1 year ago (1 children)

This is interesting. So these have the “non BT 2.4Ghz” protocol that you generally find in the huge wireless gaming headset?

Yes, exactly.

Actually "Gaming" was exactly the keyword that finally made me find these things. Looking for "normal" headsets/in-ears you can find some that also claim to be optimized for conferences and of course they also claim "low latency", but looking deeper the best they typically have are aptX-LL or something, which does shit when in duplex mode (unless yours and their bluetooth stack allow some hackery like Faststream). But the gaming-optimized ones typically offer real low latency.

Downside of in-ears is obviously the battery lifetime. I think I need to quick-charge them every 3h. But it's not often a problem, since most of the time I put them in their charging box during a short (5 minutes or so) break which is enough to boost them long enough that I don't even notice the battery through out a longer session. Upside - which I wanted them for is - that I don't have a large headset covering my ears and pressing on my head.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

These could be nice upgrade for my Pixel Buds A series. I'm using them for Teams (low latency bad quality). (Not just music high latency high quality).

However, what I really also want to have are gaming headsets (with the long microphone and low latency) that are a bit more low profile and not huge.

At first I thought it was a matter of physics, but after seeing 2.4Ghz low latency in these tiny earbuds I guess it's possible.

Can't believe low profile on-ear headsets are not popular. They are all over the ear or huge.

And as you said the ones they generally make for teams sucks with BT high duplex latency.

[–] [email protected] 2 points 1 year ago (1 children)

Overear wireless gaming headsets should be easier to find. Logitech for example builds them for ages. I also had foldable business headphones from Logitech that have their own dongle and bluetooth support.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago)

I found some but they still looked huge and flashy. Not small like the Jabras or Microsoft.

I only care about design because I plan to use them with the webcam on.

I'll take a look at the page later! Thanks

[–] [email protected] 1 points 1 year ago (1 children)

You're gonna need wired or 2.4ghz wireless for that.

[–] [email protected] 7 points 1 year ago

Technically, Bluetooth uses 2.4GHz XP

[–] [email protected] 1 points 1 year ago

When I try to fiddle with them they just start producing a hellish noise that breaks my ears in a certain configuration, I had that happen both on Jabra earbuds and Soundcore headphones, luckily the latter has a wire option as well so that's a relief