For sound bad quality, please confirm that whether it refers to the conversation or music.
1. If it refers to the sound of music:
If the sound is loud and clear but with no bass, we feel sorry to say that our car kit is ideal for conversation and the sound quality can't be compare with your car stereo.
If the sound quality is out of normal, pls try to reset the carkit, clear your phone's bluetooth list and try to reconnect.
If it doesn't make any difference, the one you get might be a defective one, pls contact firstname.lastname@example.org for a replacement.
2. If you refers to the sound of conversation:
Please check below:
Or you can also contact email@example.com for further assistant.