Freq Analyzer Scope:

  This draws a number horizontal lines in a window.  Each  line  symbolizes
  one channel in the playing module. From left to right the line symbolizes
  the given octaves of the modules. That is, when a box pops up, the  place
  where  it  appears  depends on the note being played. The higher the note
  the more to the right the box is placed. One more thing: The size of each
  box corresponds to the volume, with which the note was played.