Let me ask you what are you listening to your FX40 with.. They sound better just straight from a DAP. These are less forgiving of sound than most cheapos too so that might be another reason. You tube is not gonna have the best quality sound so these might expose some not so good quality vids you are watching.
i listen to trance,techno,rock,metal,jpop,kpop,classical,music from video games.also whats a dap?