The sound quality isnt up there with the $100 units of course, but it is fine for vocal range. either way it served its purpose for me and wasnt too expensive which is why I gave it 3stars need to research a bit (shall update if solved)Update 1: basically need to download the FIIO Music app for Android and youll get all configuration through app on the phone. Probably one of my better exercise purchases. By they, I mean the right ear bud. I am a size 14 and has to order the 3XL ??. It helps to be handy because my rear bar didnt line up I realized there was another hex head that holds the spring mechanism in place because they adjust. They have an easy warranty too. I have no relationship with any tech company. I liked it so much I bought a much bigger bottle