Hi, I own M40 and I hope I can give you satisfactory suggestion. M40 comes with in the box Type C Headphone which sounds amazing, if you have lost it or damaged and trying to buy new Type C headphone then be cautious because M40 could not support all brands Headphone. If you're able to purchase Samsung's AKG Type C headphone which comes with Samsung Flagship phone then you will able to experience different level of sound quality. Currently I have both headphone one which came with box and AKG one. If you're planning to purchase local headphone then you should try multiple headphone and update your phone to One UI 2.0. I am sure other Type C headphone will work.