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More on chord square planar scales

🔗Gene Ward Smith <gwsmith@svpal.org>

2/18/2004 2:23:07 PM

Below I give these for 3x3 and 5x5 squares of 225/224 and 2401/2400
planar. I'm using odd numbers since this removes any dependence on
the actual generators chosen, though looking at the whole list
wouldn't be that bad for even sized squares. Now, however, I only
have a prime and inverted form to worry about. What's below is a
Maple file which can be read directly into Maple if you have it.

# 3x3 and 5x5 chord squares for 225/224, [0,0,1] and [0,1,2] chord
generators

s3_225 := [[0, 0, 0], [0, 0, -1], [0, 0, 1], [0, 1, 2], [0, -1, -2],
[0, -1, -3], [0, 1, 1], [0, -1, -1], [0, 1, 3]]:

s5_225 := [[0, 0, 0], [0, -2, -2], [0, 2, 2], [0, 0, -1], [0, 0, 1],
[0, 0, -2], [0, 0, 2], [0, 1, 2], [0, -2, -4], [0, -2, -6], [0, -1, -
2],
[0, -1, -4], [0, 1, 0], [0, 2, 4], [0, -2, -5], [0, -1, -3], [0, 1,
1],
[0, 2, 3], [0, -2, -3], [0, -1, -1], [0, 1, 3], [0, 2, 5], [0, -1,
0], [0, 1, 4], [0, 2, 6]]:

# 3x3 and 5x5 chord squares for 2401/2400, [1,1,-1] and [1,1,-2]
chord generators

s3_2401 := [[0, 0, 0], [1, 1, -1], [1, 1, -2], [-1, -1, 1], [-1, -1,
2],
[-2,-2, 3], [0, 0, -1], [0, 0, 1], [2, 2, -3]]:

s5_2401 := [[0, 0, 0], [-2, -2, 2], [2, 2, -2], [1, 1, -1], [1, 1, -
2],
[-1, -1, 1], [-1, -1, 2], [-2, -2, 3], [0, 0, -1], [0, 0, 1], [2, 2, -
3],
[-2, -2, 4], [-4, -4, 6], [-3, -3, 4], [-1, -1, 0], [2, 2, -4], [0,
0, -2],
[-3, -3, 5],[1, 1, -3], [-1, -1, 3], [3, 3, -5], [0, 0, 2], [1, 1,
0],
[3, 3, -4], [4, 4,-6]]:

# corresponding 7-limit scales of notes for above chord lists

# 225/224 JI

# 20 notes
c3_225 := [1, 225/224, 15/14, 49/45, 9/8, 7/6, 135/112, 56/45, 5/4,
21/16,
4/3, 7/5, 45/32, 3/2, 14/9, 45/28, 5/3, 7/4, 28/15, 15/8]:

# 44 notes
c5_225 := [1, 225/224, 28/27, 21/20, 135/128, 15/14, 49/45, 10/9,
9/8,
2025/1792, 784/675, 7/6, 135/112, 56/45, 5/4, 2025/1568, 21/16, 4/3,
75/56,
2744/2025, 7/5, 45/32, 10/7, 196/135, 3/2, 675/448, 3136/2025, 14/9,
45/28,
10125/6272, 49/30, 224/135, 5/3, 27/16, 675/392, 392/225, 7/4, 16/9,
405/224,
28/15,15/8, 784/405, 6075/3136, 63/32]:

# 225/224-reduced using <2, 4/3, 15/14> as generators

# 16 notes
k3_225 := [[0, 0, 0], [0, 0, 1], [0, 1, -3], [1, -2, 0], [0, 1, -2],
[1, -2, 1], [0, 1, -1], [1, -1, -2], [0, 1, 0], [1, -1, -1], [1, -1,
0],
[0, 2, -2], [1, -1, 1], [0, 2, -1], [1, 0, -2], [1, 0, -1]]:

# 31 notes
k5_225 := [[0, 0, 0], [-1, 3, -2], [1, -2, -1], [0, 0, 1], [0, 1, -
3],
[-1, 3,-1], [1, -2, 0], [0, 1, -2], [1, -2, 1], [0, 1, -1], [1, -2,
2], [1, -1, -2],
[0, 1, 0], [0, 2, -4], [1, -1, -1], [0, 1, 1], [0, 2, -3], [1, -1,
0], [0, 2,-2],
[1, -1, 1], [1, 0, -3], [0, 2, -1], [2, -3, 0], [1, -1, 2], [1, 0, -
2],
[0, 2, 0], [2, -3, 1], [1, 0, -1], [0, 3, -3], [2, -3, 2], [2, -2, -
2]]:

# 2401/2400 JI

# 25 notes
c3_2401 := [1, 2401/2400, 49/48, 360/343, 15/14, 7/6, 60/49, 49/40,
5/4,
2401/1920, 450/343, 7/5, 10/7, 343/240, 3600/2401, 3/2, 75/49, 49/32,
49/30,
2401/1440, 12/7, 600/343, 7/4, 90/49, 15/8]:

# 58 notes
c5_2401 := [1, 2401/2400, 49/48, 117649/115200, 864000/823543,
360/343,
18000/16807, 15/14, 343/320, 35/32, 2700/2401, 8/7, 343/300, 225/196,
7/6,
16807/14400, 823543/691200, 60/49, 49/40, 5/4, 2401/1920,
21600/16807,
1080000/823543, 450/343, 21/16, 2401/1800, 75/56, 117649/86400,
480/343, 7/5,
10/7, 343/240, 823543/576000, 16807/11520, 3600/2401, 3/2, 75/49,
49/32,
1296000/823543, 27000/16807, 45/28, 49/30, 117649/72000, 2401/1440,
5764801/3456000,
28800/16807, 12/7, 600/343, 7/4, 16807/9600, 343/192, 216000/117649,
90/49, 28/15,
4500/2401, 15/8, 343/180, 823543/432000]:

# 2401/2400-reduced using <2, 7/5, 49/40> as generators

# 18 notes
k3_2401 := [[0, 0, 0], [1, -2, 0], [-1, 1, 2], [0, -1, 2], [1, -1, -
1],
[0, 0, 1], [1, -2, 1], [0, -1, 3], [0, 1, 0], [1, -1, 0], [0, 0, 2],
[1, -2, 2],
[1, 0, -1], [2, -2, -1], [0, 1, 1], [1, -1, 1], [0, 0, 3], [1, -2,
3]]:

# 33 notes
k5_2401 := [[0, 0, 0], [1, -2, 0], [-1, 1, 2], [0, -1, 2], [1, -3,
2],
[-1, 0,4], [0, 1, -1], [0, -2, 4], [1, -1, -1], [2, -3, -1], [0, 0,
1],
[1, -2, 1], [-1, 1, 3], [0, -1, 3], [1, 0, -2], [1, -3, 3], [2, -2, -
2],
[0, 1, 0], [1, -1,0], [2, -3, 0], [0, 0, 2], [1, -2, 2], [-1, 1, 4],
[0, -1, 4],
[1, 0, -1], [2,-2, -1], [0, 1, 1], [1, -1, 1], [2, -3, 1], [0, 0, 3],
[1, 1, -2],
[1, -2, 3], [2, -1, -2]]: