play it in http://studio.substack.net (about code-music-studio:http://dailyjs.com/2014/04/17/code-studio/)

electric_guitar_remix.coffee

###
# electric guitar remix
#   version 1.1 ( with organ harmony , heart beat)
#
# electric_guitar_remix.coffee
#   Source: https://gist.github.com/KC-Liu/11139685
#   
# Inspired by "Mom, I got full marks in the exam" by SelfKill
#   (https://www.youtube.com/watch?v=jq6bvDQ2FyA)
#
# Coded by Kunjie
#  (https://github.com/kc-liu)
###
 
###
# constants
###

VOLUME = {solo:0.3,bass:0.4,drum:0.6} 
BPS = 5
TAU = 2 * Math.PI
na = null
 
###
# notes
###
 
SOLO = [0, 2, 4, 0, 7, 4, 0, 9,  na, 11, 9,  7,   4,  5, 7,  na,
        0, 2, 4, 0, 7, 4, 0, 11, na, 11, na, na, 12, na, 11, na,
        5, 7, 9, 5,12, 9, 5, 16, na, 16, 14,  9, 12, na, 11, na,
        5, 7, 9, 5,12, 9, 5, 16, na, 16, na, na, 17, na, 16, na ];
BASS = [12,11,11,12,
        11, 9, 9, 7,
        12,11,11,12,
        14,16,14,12 ];
 
###
# sound effect
###
 
harmony = (tt,freq) ->
	Math.sin( TAU * tt * freq ) * Math.sin( tt % 6 * TAU)
 
pluck = (tt,freq,duration,steps) ->
	_sum = 0
	_scalar = Math.max( 0 , 0.95 - (tt * duration) / ((tt * duration) + 1) )
	for i in [0...steps] by 1
		do(i) ->
			_sum += Math.sin( TAU * tt * (freq + i * freq ) )  
	return _scalar * _sum / 16
 
drums = (tt) ->
	_s = tt * 0.75 % 5 +1
	_f = Math.sin( 2 * TAU / (16 * _s % 2 + 0.5) * 1.2 )
	Math.sin( TAU * _s * _f)	
 
 
###
# music
###
 
return (t) ->
	note = (tt,song) ->	
		_f = song[ Math.floor( tt % song.length ) ]
		if  _f?
			(2 ** (_f / 12) ) * 240
		else
			0
	_m = note( t * BPS , SOLO )
	_b = note( 0.25 *t * BPS , BASS )
	pluck( t % (1 / BPS) , _m , 10 , 50 )* VOLUME.solo + drums( 0.25*t % (1 / BPS )) * VOLUME.drum + harmony( t , _b ) * VOLUME.bass