u/RogerKangaroo

I was listening to Clint Eastwood and i realized I sometimes hear and sometimes don't hear the "It's all in your head" line. I thought it was either played in left or right ear but when i take out my earphones i can hear it in both ears. The weird part is when I only take one of my earbuds from their case I can't hear the line on either bud. But when i take both out of the case and listen individually i can hear it in each ear. How did they do this, am I going schizophrenic?