Find out which codec your Bluetooth headphones are using on MacOS Sonoma 14 or later

• Disconnect your Bluetooth headphones or speakers
• Start the Console app

• In the top right column, filter by PROCESS bluetoothd and MESSAGE codec

• Connect your headphones or speakers
• Look for a line that starts with “A2DP configured…”.

The full message will read something like: A2DP configured at 44.1 KHz. Codec: AAC-LC, VBR max: 256kbps...

This means your codec is AAC-LC.