Chapter 4 - How built-in synths are defined in Sonic Pi

The synth beep

Let’s look at this, as it is what we are reimplementing:

class Beep < SonicPiSynth
  def name
    "Sine Wave"
  end

  def introduced
    Version.new(2,0,0)
  end

  def synth_name
    "beep"
  end

  def doc
    "A simple pure sine wave. The sine wave is the simplest, purest sound there is and is the fundamental building block of all noise. The mathematician Fourier demonstrated that any sound could be built out of a number of sine waves (the more complex the sound, the more sine waves needed). Have a play combining a number of sine waves to design your own sounds!"
  end

  def arg_defaults
    {
      :note => 52,
      :note_slide => 0,
      :note_slide_shape => 1,
      :note_slide_curve => 0,
      :amp => 1,
      :amp_slide => 0,
      :amp_slide_shape => 1,
      :amp_slide_curve => 0,
      :pan => 0,
      :pan_slide => 0,
      :pan_slide_shape => 1,
      :pan_slide_curve => 0,

      :attack => 0,
      :decay => 0,
      :sustain => 0,
      :release => 1,
      :attack_level => 1,
      :decay_level => :sustain_level,
      :sustain_level => 1,
      :env_curve => 2
    }
  end
end

To make our reimplementation a first-class Sonic Pi synth we will create a new Class for it, inheriting from SonicPiSynth and implement the following functions:

• name
• arg_defaults
• introduced
• synth_name
• doc

In addition we will need to add an entry into @@synth_info.