Instruct: Classify Amazon reviews into positive or negative sentiment
Query: earbuds never fit, no matter what

I've tried to get the earbuds to stay in, and no matter which technique I try, they never do. I've changed sizes, seating positions, etc., and they always pop out. If they're not fitted properly the sound is terrible--no bass at all. Once in, they sound great. But if I'm using them on the treadmill, they pop out in seconds--even after I've fitted them by pulling up on my ear.