Based on the principles of Longplayer’s composition, Shortplayer is any composition of duration d (whatever units of time you choose) made by the action of an algorithm, described below, on n pieces of source music.
Thus Longplayer itself is one instance of such a composition.
Compose a piece of music of length l made of x notes of specified pitch, duration and placement in time.
Instrumentation can be anything one chooses and need not be the same for each note. Monophonic instrumentation is recommended as is the inclusion of periods of silence.
Make as many transpositions, of any intervals, as you choose such that the number of transposed pieces + the original piece = n.
Length of composition is d.
The algorithm chooses a new start point from which to play for each of the n pieces of source music once every p units of time.
Every p the start point is moved on from the previous start point by adding an increment to the previous start point. Then play for p units of time.
For each of the n pieces of source music choose an increment, i, such that at the end of d (ie the end of the piece) each start point is 0 (zero, ie the piece ends at the precise point at which it started – all start points being zero, ie a loop !).
For example: if d (the duration of the composition) is 60 minutes, l, the length of the source music, is one minute and p is one minute then one possible choice of the value of i would be one second, 1/60th minute.
Over the course of the 60 minutes duration the start point would move once through the one minute / 60 second long piece of source music once.
If i is 3 seconds then the start point would move through the source music 3 times (each 20 iterations the start point would arrive back at the beginning – let’s call these orbits (denoted by z). In this case there would be 3 orbits of the source music ie z = 3).
Each value of i, for each piece of source music, should be different and preferably, for the sake of maximum variety, not exactly divisible by other values of i.
(Though it’s good to have increments that will divide neatly into the length of the source music . . . unless a different physical score is used, as in Longplayer’s circular score)
A way to work these out is to choose different orbits / values of z and use this formula to work out each value of i:
i = z * l / (d / p)
[increment = (orbits times length of source music) divided by (duration of composition divided by period)]
d = 60 minutes (duration of composition)
l = 1 minute (length of each piece of source music)
n = 5 (pieces of source music)
p = 1 minute
z = 1, 3, 5, 8, 11 seconds
i(1) = 1 * 1 / (60 / 1) = 1/60 minute = 1 second
i(2) = 3 * 1 / (60 / 1) = 3/60 minute = 3 seconds
i(3) = 4 * 1 / (60 / 1) = 4/60 minute = 4 seconds
i(4) = 5* 1 / (60 / 1) = 5/60 minute = 5 seconds
i(5) = 8 * 1 / (60 / 1) = 10/60 minute = 10 seconds
[note that in this example i(5) is a multiple of i(4). Not ideal but necessary – for the sake of simplifying the scores each value of i must divide exactly into l. If the written score is presented as a circle – as is the case with Longplayer – then i only needs divide equally into the sum of all orbits, z x l]
Notate each transposition. At the end of the notation repeat the section from zero seconds to the width of the window (see below for details as to calculation of window width).
Draw a vertical line every i units of time.
Make a window whose horizontal dimension is equal to p multiplied by the transposition (eg p is 1 minute. For the fundamental piece of source music transposition = 1, ie no transposition, so window length = p = 1 minute. For a transposition of an octave below, transposition = 0.5, so window length = 30 seconds). This procedure dictates how much musical material is got through in period p according to transposition. Think of it like speeding up or slowing down a record.
Regardless of the window width take p units of time to play through it.
The start of the window is moved along to the next vertical line each p units of time.
If the start point is the end of the source music return window to the start of the source music.