Why does my audio quality decrease when the mic is on?

Because of Bluetooth limitations on many headphones it's normal for the audio quality to drop when using the mic due to the way Bluetooth works.

In normal usage, it will be using A2DP, which allows for Stereo sound and high quality codecs likes aptX, AAC and LDAC.

When using the mic, it will switch to HFP (Hands-Free Profile), the audio streams are then split from Left and Right, to Inbound and Outbound. This forces the headset into Mono mode. Support for better codecs is limited, so your audio quality will also drop.

Windows 10 and 11 have improved Bluetooth support out of the box, but it still isn't perfect.

Two Bluetooth headsets for work we've tested that don't degrade the audio when the mic is active is the Epos Impact 1000 and Orosound Tilde Evo. We're sure this will be the new standard with Bluetooth headsets going forward.