Swap audio channels?

Is there a way to swap the audio channels coming out of the headphone jack on my tablet? A third-party app would be acceptable. For some context: My tablet has a pop in the left channel and I need it to pop in the right instead. I'm using the left channel to play background music through a large PA system and the right channel with notes to myself that only I can hear. I separate the left channel out to the PA and then plug them both into a mixer for myself. The PA gets the left (with the pop) and I get both. Since the pop is only in the left, if I could swap the channels, I could just swap my external wiring and voila, only "I" hear the pop, not the PA system.