In music theory, phasing is a compositional technique in which the same sequence of notes are played over and over again by two instruments, one of which continuously increases its tempo. This creates a number of interesting effects. First one instrument seems to echo the other. Then each note is doubled. Then the notes begin to sound like they're ringing, until finally, the up-tempo instrument loops totally around, and the instruments are completely in sync again.
What phasing demonstrates is that a musical composition isn't just influenced by its arrangement of notes, but by the tempo and combination in which they are played. Musicians such as Brian Eno and Sufjan Stephens have made use of phasing in their albums, even if you don't realize it. But you'll be able to spot it immediately next time you see it thanks to Piano Phase, a new visualization by Google creative director Alexander Chen, that shows how phasing works.
Previously on Co.Design for his strummable MTA Subway Map and animating the Beach Boys' pop ecstasy, Chen is a master of musical visualizations. (He was also the creator of the popular Les Paul Google doodle.)
With Piano Phase, Chen visualizes a twelve note sequence from Steve Reich's 1967 piece of the same name. In that piece, two pianists repeat the same notes, but one gradually speeds up, so that he is playing the second note while the other pianist is playing the first. Eventually, by the end of the piece, the two pianists completely sync up again. It's a complicated process to wrap your head around, but by animating the two pianos independently as a duo of red and blue lines, Chen makes what is happening in the piece seem more intuitive.
Even if you don't care about phasing though, Chen's Piano Phase visualization is neat to look at, almost like an animated piano duel.
You can check it out here.