Fairbuds-XL + Linux: How to improve bluetooth voice quality in headset mode

I recently received my Fairbuds XL. While music works fine (after struggling with several Linux vs. Bluetooth vs. Intel vs. PulseAudio vs. Pipewire issues), headset only delivers horrible quality.

Using pipewire in Linux Mint I have the following options

  • High Fidelity Playback (A2DP Sink, codec SBC)
  • High Fidelity Playback (A2DP Sink, codec SBC-XQ)
  • Headset Head Unit (HSP/HFP, codec mSBC)
  • Headset Head Unit (HSP/HFP, codec CVSD)

I don’t hear a difference between mSBC and VCSD (both sound horribly compressed). Does that mean that mSBC might not be working (it should sound better, I think) or is the difference too subtle?

Is there anything missing from this list? The website states the following Bluetooth details:

  • Bluetooth: 5.1
  • A2DP V1.3.2
  • AVRCP V1.6.2
  • GAVPD V1.3 (I guess this should have been GAVDP)
  • HFP V1.7.2
  • HSP V1.2

But no codecs are listed. So I don’t know whether the headphones support anything better (FastStream maybe?) and my system just lacks some codecs.

Did anyone achieve an “ok” voice quality? (answers in German are fine, too)

(I still need to test the quality on Android (Lineage))

Updated Firmware to V90 (not sure if this changed anything related to this topic).

Well … just did another test. Recording my own voice and listened to music in mSBC and VCSD.

Now the difference is obvious! While VCSD uses 16 kbps up/down it sounds significantly worse (both directions) than mSCB which only uses 8 kbps. mSCB has an acceptable quality for a simple phone call.

Another oddity: While switching the profiles the headphone volume jumped to 100 % (which was too loud) and the mic as well (which was too silent). After a few switches the recorded microphone went from way too silent to perfect for mSCB and stayed too silent for VCSD.

Switching is super annoying and seems non-deterministic. At least I now know it’s possible to get the best out of my Fairbuds, once I manage to tame the software setup.

Another thing I found out (don’t laugh!) is that the USB-cable can be used to get a perfect wired headphone - I thought it would only be used for charging, which was the case with my former headphones.

It’s a pity that I didn’t find these information on the product page, because knowing about this fallback would have made me buy them months ago. I wasn’t even sure it could be used as a headset because it’s only advertised as “Headphones”.

Ok, long story short: my initial question is kind of solved, but I’d like to hear about your experiences and maybe some explanation about that weird behavior I found. … and if AptX should have been listed somehow in the codecs …

Headset unit will sound bad for music with any BT headset as it’s a feature of the codec so if you are listening to music using something without microphone in pipewire will sound better.

Aptx HD would be supported, but it’s not shipped by any Linux distribution, on Fedora it would be in package pipewire-codec-aptx from rpmfusion-free-updates repository.

I don’t feel comfortable sending Linux Mint (or Ubuntu) instructions since I don’t use those and I don’t know how correct or safe those are, but you can find them by “aptx hd linux mint” in your favorite search engine. It seemed to involve adding a PPA, which makes me hesitant with just cursory glance.

Edit: sorry if this is outdated for you, I just receiced email notification about this thread and only after posting noticed that I am responding two months late.

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