155 lines
3.8 KiB
Python
Executable file
155 lines
3.8 KiB
Python
Executable file
#!/usr/bin/python
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from data import *
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stock = []
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stock += daddario_plain_steel
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stock += daddario_nickle_wound
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#stock += circle_k_plain
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#stock += circle_k_hybrid_wound
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mm_to_in = 0.03937
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scale_length = 648*mm_to_in
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string_sets = {
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'regular light': (
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# (desired note, tension, and type)
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('E4' , 16, 'P'),
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('B3' , 16, 'P'),
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('G3' , 16, 'P'),
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('D3' , 16, 'W'),
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('A2' , 16, 'W'),
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('E2' , 16, 'W'),
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),
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'jazz light': (
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('E4' , 24, 'P'),
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('B3' , 24, 'P'),
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('G3' , 24, 'W'),
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('D3' , 24, 'W'),
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('A2' , 24, 'W'),
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('E2' , 24, 'W'),
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),
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'regular light (DADGAD)': (
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('D4' , 16, 'P'),
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('A3' , 16, 'P'),
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('G3' , 16, 'P'),
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('D3' , 16, 'W'),
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('A2' , 16, 'W'),
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('D2' , 16, 'W'),
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),
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'regular light (open G, 6)': (
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('D4' , 16, 'P'),
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('B3' , 16, 'P'),
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('G3' , 16, 'P'),
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('D3' , 16, 'W'),
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('B2' , 16, 'W'),
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('D2' , 16, 'W'),
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),
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'regular light (open G, 7)': (
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('D4' , 16, 'P'),
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('B3' , 16, 'P'),
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('G3' , 16, 'P'),
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('D3' , 16, 'W'),
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('B2' , 16, 'W'),
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('G2' , 16, 'W'),
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('D2' , 16, 'W'),
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),
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}
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A = 440
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notes = {
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'C' : 0,
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'D' : 2,
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'E' : 4,
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'F' : 5,
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'G' : 7,
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'A' : 9,
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'B' : 11,
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}
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rel = (2**(1/12.))
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def note2freq(name):
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sharp = name[1] == '#'
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flat = name[1] == 'b'
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if sharp or flat:
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note = name[0:1]
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octave = int(name[2])
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else:
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note = name[0]
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octave = int(name[1])
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num = notes[note]
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if sharp:
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num += 1
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if flat:
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num -= 1
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fullnum = num + 12*(octave - 5)
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return A*rel**(fullnum + 3)
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def test(name, expected):
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print('{:3} gave {: 9.2f} Hz\nexpected {: 9.2f} Hz'.format(name, note2freq(name), expected))
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if False:
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test('C2' , 65.41)
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test('Ab4', 415.30)
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test('A4' , 440.00)
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test('B4' , 493.88)
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test('B#4', 523.25)
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test('Cb5', 493.88)
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test('C5' , 523.25)
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print()
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test('E4' , 329.63)
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test('B3' , 246.94)
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test('G3' , 196.00)
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test('D3' , 146.83)
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test('A2' , 110.00)
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test('E2' , 82.41)
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import sys
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sys.exit(0)
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uw_const = 386.4
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def uw2tension(uw, freq):
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return (uw*(2*scale_length*freq)**2)/uw_const
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def tension2uw(t, freq):
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return (t*uw_const)/(2*scale_length*freq)**2
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if False:
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scale_length = 25.4825
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D3 = note2freq('D3')
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print('NW024 {:10.8f} == 0.00010857'.format(tension2uw(15.73, D3)))
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print('NW025* {:10.8f} == ? '.format(tension2uw(17.21, D3)))
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print('NW026 {:10.8f} == 0.00012671'.format(tension2uw(18.38, D3)))
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import sys
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sys.exit(0)
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outfmt = '{:<6} at {:> 5.2f} lbs ({:>+4.2f})'
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finalfmt = 'total: {:>7.2f} lbs ({:>+5.2f})'
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def print_ideal_stock(strings):
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total_tension = 0
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total_desired_tension = 0
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for note, tension, kind in strings:
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freq = note2freq(note)
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uw = tension2uw(tension, freq)
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closest = ('n/a', 0)
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for name, stock_uw in stock:
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if kind == 'P' and name[2] != 'P':
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continue
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if kind == 'W' and name[3] != 'W':
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continue
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if abs(stock_uw - uw) < abs(closest[1] - uw):
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closest = (name, stock_uw)
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closest_tension = uw2tension(closest[1], freq)
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diff = closest_tension - tension
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print(outfmt.format(closest[0], closest_tension, diff))
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total_tension += closest_tension
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total_desired_tension += tension
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error = total_tension - total_desired_tension
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print(finalfmt.format(total_tension, error))
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print('for a scale length of {:>5.2f} inches'.format(scale_length))
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for name, strings in string_sets.items():
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print()
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print('"{}"'.format(name))
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print_ideal_stock(strings)
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