Thank you for contacting us about you Bluetooth adapter. I’m sorry about the problems with it.
It is possible that the adapter is connecting to the headphones using the headset profile (HSP/HFP) instead of the headphones profile (A2DP). This will cause a big difference in sound quality.
To check this, please right-click on the speaker icon on the lower right of your screen near the clock and select Playback devices. You headphones will possibly be listed under two headings: Headphones and Headset. Right-click the Headphones one and select Set As Default Device. If this doesn’t work, please let me know, and we can look deeper into what’s happening.
If the adapter is faulty, we’ll send you a replacement right away.