Music doesn't work during gameplay
Recently I got the iPod 6th generation. When I listen to music through apps like iTunes or spotify, or watch videos on apps like youtube and Netflix the volume works fine, but when I play any game, the sound does not seem to work, I have checked in apps such as Geomontry Dash, Minecraft, Piano Tiles 4, Kill Shot, and multiple others. The sound for notificatios works also. I have checked game settings, and even exchanged my iPod for a new one because of that problem today, but the new iPod I got (the same version) has the same problem.
iPod touch, iOS 9.1