Headset delivers bad audio quality and low microphone volume in HSP/HFP mode (bluetooth)
Audio playback quality in HSP/HFP mode (bluetooth) is bad, microphone record volume is way too low
- Fedora 31
- pulseaudio 13.0-rebootstrapped
- bluetoothctl 5.52
- kernel 5.3.14
- Hardware: Teufel Airy (2017) headset
Steps to reproduce
I own a Teufel Airy (2017) bluetooth headset (bluetooth 4.0, aptX support) and like to use it as a headset through bluetooth on Fedora 31. The headset pairs fine via the gnome ui. The settings dialog allows me to connect it in A2DP mode (just playback, good sound quality) and in HSP/HFP mode.
What is the current bug behavior?
In HSP/HFP mode playback quality is bad, the microphone seems to work, but the record levels are way too low. Knocking directly on the microphone produces just 3 to 8 dashes in the picture below. Speaking very loud only 1 dash.
What is the expected correct behavior?
Audio quality stays like in A2DP mode, microphone records at an acceptable volume.
If connected to my Android 9 phone, the playback quality is fine, the record quality is fine and playback quality in phone calls is also fine.
I guess some part of the bluetooth system isn't supporting something or is misconfigured, but I don't know which part. I found this bugreport on launchpad mentioning the issue and a possible solution which seems to be applied in ChromiumOS - they stated that the kernel/bluetooth stack isn't supporting modern HSP/HFP modes.
I've been told by the gnome-team to report the issue here. I hope this channel is suited to receive the bug report. If not, please report it to an appropriate upstream project, like bluez or the linux kernel. I'd be happy to assist in gathering more logs.
Furthermore I think these bugs might be related:
I think the bluetooth device is A0_E9_DB_01_7E_D0