On Phase Shifting

Without Reich, Math-Rock would have evolved into something somewhat duller. Extend this generic intro for your own pleasure if you like, but let’s write phasing. Phase shifting, in it’s simplest form, consists of two identical lines of music played at steady but very slightly varying tempos. Over time the lines will appear to fall out of time with each other. If the lines are looped, which they generally are in phasing, the music will appear, after a while, to fall back into time. This effect is very easy to achieve with, for example, two different tape players from Reich’s era playing identical tapes (tape players very rarely played cassettes at the same speed, although the variation was very subtle), but performing phasing live introduces a few difficulties.
 To begin with, it is very, very hard to ignore what is happening sonically around you. This becomes exponentially harder when you are trying to play the same looped line as the Korg SV1 88 Note ‘Stage Vintage’ Keyboard next to you, but at a slightly varied tempo. Furthermore, if you can ignore the sound around you, it would be incredibly difficult to create a tempo only so slightly varied as to allow the music an extended amount of time to evolve. A system, therefore, was created to overcome this.
 Phase shifting live, is very much the same as a round. The difference being once a line starts in a round it continues to the end and finishes or loops indefinitely at a defined interval to the other lines. Phasing allows the line freedom to move in time. It can be achieved by adding notes. So the first line loops indefinitely. The second line loops at first in phase with the first line, but at a determined moment the last semi-quaver in the line is shifted to the beginning of the bar, thus moving the line a sixteenth note out of time with the initial line. This practise can then be continued. Furthermore, rather than performing the melodies in time to begin with, introduce a few layers of the same melody, note-by-note, layer-by-layer, until a harmonically static texture is created of out-of-sync identical lines.
 The technique is as simple as that, and although it may not be a common mode of composition in math rock, texturally the influence is huge (just listen to Don Caballero 3 from What Burns Never Returns). Maybe I’ll explore polymeters next.
For now, a man playing Piano Phase on two pianos, little treat.

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