Sonic Pi: untitled composition refactored

gistfile1.txt

# based on https://vimeo.com/50061269 by Andrew Sorensen
# refactored and clarified
use_bpm 90
use_synth :dsaw

# five loops, each has a volume from 0 to 1
volumes = [0, 0, 0, 0, 0]

# play a pattern of <notes> with <amps>, with <time> between notes
# use loop index <loop> for the note volumes
# play <count> notes total
# notes and amps should be rings so they can be cycled through
define :pat do |a|
  with_fx :reverb do
    a[:count].times do |i|
      # volume varies randomly around the specified level
      variance = rrand(0, 0.1)
      play a[:notes][i], amp: volumes[a[:loop]]*(a[:amps][i] + variance), 
        release: a[:rel] || a[:time]
      sleep a[:time]
    end
  end
end

# all the live loops start at the beginning of the composition,
# but the volumes are turned down initially

# simple two-note pattern with a triplet feel (LA-da-la-DA-la-da, etc.)
# since the rings repeat, this gives 6 notes with:
# note: c4  eb4 c4  eb4 c4  eb4
# amp:  .3  .2  .2  .3  .2  .2
# three notes per beat, doodle loops every 4 beats
live_loop :doodle do
  pat loop: 0, count: 12,
    notes: (ring :c4, :eb4), amps: (ring 0.3, 0.2, 0.2), 
    time: 1/3.0, rel: 0.45
end

# the other loops all sync on doodle, setting auto_cue:false 
# keeps them from creating their own cues, which just clutter up the log

# same two-note pattern, a fifth higher
live_loop :noodle, auto_cue:false do
  sync :doodle
  pat loop: 1, count: 12,
    notes: (ring :g4, :bb5), amps: (ring 0.2, 0.1, 0.1), 
    time: 1/3.0, rel: 0.4
end

# bass, 8 beats per note
live_loop :boodle, auto_cue:false do
  sync :doodle
  pat loop: 2, count: 8,
    notes: (ring :c4, :bb3, :ab3), amps: (ring 0.35, 0.3, 0.3), 
    time: 8 if volumes[2] != 0 # don't start playing until we fade in, keeps in sync better
end

# offset bass note, one beat after downbeat
live_loop :foodle, auto_cue:false do
  sync :doodle
  sleep 1
  pat loop: 3, count: 8,
    notes: (ring :eb4), amps: (ring 0.4, 0.3, 0.3), 
    time: 8, rel: 7 if volumes[3] != 0
end

# high arpeg
# triplet feel with six notes per beat
live_loop :arpoodle, auto_cue:false do
  sync :doodle
  pat loop: 4, count: 24,
    notes: (ring :bb5, :eb5, :g6, :eb5, :g6, :eb5), amps: (ring 0.2, 0.1, 0.1), 
    time: 1/6.0 if volumes[4] != 0
end

# This is still at time=0, all the loops are running, but muted
# fade in each loop, one at a time, in 8 beats per loop
5.times do |loop|
  8.times do
    volumes[loop] += 1/8.0
    puts volumes
    sleep 1
  end
  sleep 16 if loop > 1 # wait some extra time between the longer loops
end

# phase 2
# cycle volumes for each loop separately according to sine curves with different periods
# the periods are primes, meaning the exact pattern doesn't repeat for 7*11*13*17*19 seconds
# which is about 3.75 days
# graph: https://www.desmos.com/calculator/cgxksmsuwk
live_loop :finoodle, auto_cue: false do
  factors = [7, 11, 13, 17, 19]
  5.times do |loop|
    # vt is the current time in beats
    volumes[loop] = Math.sin(vt/factors[loop])*0.75 + 1
  end
  puts volumes
  sleep 1
  # add some ambience occasionally, almost in key but slightly dissonant
  sample :ambi_glass_hum, amp: 0.3, rate: pitch_ratio(3) if one_in(24)
end