# Lesson 17

# Effects Lesson. In this lesson,
# you will learn how manipulate
# synthesizer and sample sounds,
# and add special effects to the
# sounds

# General Instructions:
#
# This lesson contains three examples and
# three exercises (A, B, C).
#
# To listen to an example, change "comment"
# to "uncomment" on the "comment do" line,
# then click the "Run" menu command at the
# top of the Sonic Pi editor window.
# When you are done with the example, turn
# it off by changing "uncomment" back to
# "comment," and move on to the next section
# of the lesson.
#

# Example 1: Manipulating synthesizer sounds.
# Sonic Pi contains a number of synthesizers,
# each one having an arrange of options that
# you can change in your code. In this example,
# we use the Mod_fm synth to create a sliding,
# siren like sound. You can find descriptions
# of the various options in the help section
# for each synthesizer.

comment do
  use_bpm 50
  use_synth :mod_fm
  amplitude = 1
  center = -1
  up = true
  loop do
    play 60, duration: 4, mod_wave: 3, mod_phase: 4, mod_range: 12, amp: amplitude, pan:center
    sleep 2
    if (amplitude < 2 && up == true)
      amplitude += 0.25
      center = -1
    elsif (amplitude >= 2 && up == true)
      amplitude -= 0.25
      center = 0
      up = false
    elsif (amplitude > 0.25 && up == false)
      amplitude -= 0.2
      center = -1
    else
      amplitude += 0.25
      center = 1
      up = true
    end
  end
end

# Exercise A:
#   Find the following synths in the help
#   section and try experimenting with the
#   parameters described. Alter the code
#   in Example 1 accordingly.

#   Dark Ambience (:dark_ambience)
#   Growl (:growl)
#   Mod Pulse (:mod_pulse)

# Example 2: Manipulating sample sounds.

comment do
  amplitude = 2
  center = 0
  width = 0.1
  cutoff = 70
  lpf_change = 7
  s_rate = 1.25
  s_rate_change = 0.1
  up = true
  loop do
    sample :ambi_piano, amp: amplitude,
      pan:center, lpf: cutoff, rate:s_rate
    sleep 1
    if (amplitude < 3 && up == true)
      amplitude += 0.25
      width += 0.1
      cutoff += lpf_change
      center = -1
      s_rate += s_rate_change
    elsif (amplitude >= 3 && up == true)
      amplitude -= 0.25
      center = 0
      width -= 0.1
      cutoff -= lpf_change
      s_rate -= s_rate_change
      up = false
    elsif (amplitude > 1.0 && up == false)
      amplitude -= 0.2
      width -= 0.1
      center = -1
      cutoff -= lpf_change
      s_rate -= s_rate_change
    else
      amplitude += 0.25
      center = 1
      width += 1
      cutoff += lpf_change
      s_rate += s_rate_change
      up = true
    end
  end
end

# Exercise B: Experiment with the various
# parameters in Example 2. Look up the
# reference for the :ambi_piano sample
# in the Samples section of the help menu.
# Try adding and changing other parameters
# for that sample. Note the places where
# parameter values might go out of bounds
# (the Output window on the top right of
# Sonic Pi can be helpful). Try using
# other samples and their parameters.
# Experiment with negative rate values,
# result in backward-playing samples.
#

# Example 3: Adding effects.

comment do
  amplitude = 1
  amp_change = 0.2
  phase = 3.0
  phase_change = 0.5
  use_synth :prophet
  up = true
  note = 60
  loop do
  with_fx :flanger do
    play note, amp: amplitude, duration: 1.75,
      phase: phase
    sleep 2
    if (amplitude < 3 && up == true)
      amplitude += amp_change
      phase += phase_change
      note += 1
    elsif (amplitude >= 3 && up == true)
      amplitude -= amp_change
      phase -= phase_change
      note -= 1
      up = false
    elsif (amplitude > 1.0 && up == false)
      amplitude -= amp_change
      phase -= phase_change
      note -= 1
    else
      amplitude += amp_change
      phase += phase_change
      note += 1
      up = true
    end
  end
end

end

# Exercise C:
# Experiment by changing the parameters in
# Example 3. Look up other types of effects
# in the Fx menu and experiment with them
# in Example 3.
#