Back in 1971, my brother recorded my senior year band concert. I played the slush pump (trombone). It took place in the gymnasium on the floor. The mics were on the stage a long way from the music. Because it was recorded so far away, it wasn't exactly stereo. At one point for some dumb reason I just eliminated one track, thus making it mono. Would it be possible to copy the one track to the other on the same mp3? Can you do such a thing?