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Bluetooth microphone defaults back to SCO  



So lately I've been trying to use my bluetooth headphones (Senneheiser 4.50 BTNC) for audio input and output, but this always results in my codec switching back to SCO (even though my headphones support APTX). I'm aware that you can fix the audio issue by switching back to the computer mic, but I haven't found any solution that allows me to continue using my headphone mic.

I've tried using bluetooth explorer to force APTX and using terminal to set APTX on and SCO off, but it always ends up defaulting back to SCO when I use the bluetooth mic. Anyone know a solution to this?

2 Answers

Seems that Bluetooth doesn't support AptX (or any other "high quality" codec) when a microphone is in use. I think it has to do with the fact that Bluetooth's bandwidth is limited, and the bidirectional nature of having both channels open means bandwidth has to be carved up a little differently. has some notes on this.


My MacBook Pro (2017) supports Bluetooth 4.2, and my headphones switch to SCO for conversations. MacBook Pros got Bluetooth 5.0 in 2018.

I'm considering a USB dongle for BT5.0, like the Avantree DG60 or 1Mii B10, which both claim aptX HD support. Hopefully I'll get native support in Preferences (both Bluetooth and Sound) and Bluetooth Explorer and Audio MIDI Setup.

I have a 2018 MacBook Pro with Bluetooth 5.0 but that doesn't solve this issue, when the headphone's mic is active there's still fallback to SCO. There seems to be no way to change this configuration.


@Jensvd is right: if you're using bi-directional audio, Bluetooth Classic Audio cannot use a higher bandwidth codec for received audio.

Bluetooth LE Audio (announced at CES in January ) aims to offer a lot of enhancements. As with any structural changes, both host devices and client devices must support the new standard.