(bill tesar) with the advent of multi-track recording, you can actually record yourself several timese piece of tape without erasing what you've already done. each person is recording on a different line on that tape. so the tape recorder is recording me on let's say not the whole 2 inch width of the tape, but maybe an eighth of an inch. and someone else gets the next eighth of an inch. you can see what we call the meter bridge and actually see all the sounds of the individual musicians when they're playing; when they're not playing. [saxophone plays "what child is this"] let's just say the band plays a five-minute piece of music, and everybody loves what they played. oh, it was just so perfect. but one person just made one dumb mistake and played something and missed a note or their finger slipped, and they hit something they didn't want. and it was just one note. we have the ability for that person to play-- let's, for example, just say that they meant to play this [plays scale] and they played [plays chord with one missed note] well, the tape recorder can actually go back, after th