sound when playing with m3 simply

hi ,just got a m3 ds simply card and the sound sound worse than an original game card when the game is loading and especially on quiet moments when im listing through headphones. This is normal right`?

it doesnt bother me much but u can hear a summing when u are playing backup games on m3 ds simply,(especially when its quiet like i said)

 

specifics please. as in headphone model [yes it counts], game, sd card, etc.