I have bought a Bluetooth headset recently. After connecting the device, I was quite disappointed with the sound quality. Fortunately, after searching on the web, it seems that I am using the "Telphony Duplex" mode, which has low quality.
Here are the steps to switch to the mode with better sound quality:
- Left click on the "Bluetooth icon" on the top right corner.
- Move the cursor to your connected device.
- Left click on "Sound Settings ..." menu item.
- Change the mode from "Telphony Duplex (HSP/HFP)" to "High Fidelity Playback (A2DP)".
Reference: Ubuntu Forums: Bluetooth Headset Bad Sound Quality.