安い電子ピアノの音を作った。ProcとFiberで周波数を返すことで、倍音の合成を楽にした。

electricpiano.rb

require 'dxruby'

piano = [0.419414141440249,
0.166971777138902,
0.235853904101082,
0.0470590406691173,
0.0373803247025181,
0.00373803247025181,
0.0166971777138902,
0.0419414141440249,
0.0059243822153007,
0.00419414141440249,
0.0013263039698352,
0.00470590406691173,
0.00235853904101082,
0.00296922473343717,
0.000528011120724962,
0.0026463243292058,
0.000938951304256777,
0.000419414141440249,
0.00118206965736613,
0.000664726617590573,
0.000528011120724962,
0.000333152494588633,
0.000333152494588633,
0.000373803247025182,
0.000296922473343716,
0.000333152494588633,
0.000264632432920579,
0.000235853904101082,
0.000187345415297443,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067,
0.00001053520691067]

height = [261.6,293.7,329.6,349.2,392.0,440.0,493.9,523.3]


p = Proc.new do
  last = 0
  8.times{|t|
    1000.times{Fiber.yield(last = height[t])}
  }
  loop{Fiber.yield(last)}
end

vol = 64

s = nil
piano.each_with_index do |v,i|
  f = Fiber.new(&p)
  if i == 0
    s = SoundEffect.new(8000, WAVE_SIN){
      [f.resume * (i + 1), vol * v]
    }
  else
    s.add(WAVE_SIN){
      [f.resume * (i + 1), vol * v]
    }
  end
end

s.play
Window.loop{}