Once the main game has been completed (The player has completed the Hard track, ' The Greater Crater') for the very first time, during the credits of the game, a Morse code can be heard in the background noise, the code has been cracked and reads, "Set Spectrum display to Logarithmic Scale"
NOT THAT WE HAVE NO INFORMATION ON WHAT THE AMBIENT NOISE MENTIONED IN THE VIDEO IS, FOR NOW WE WILL TAKE IT AS PART OF THE PROCESS OF DECIPHERING A MORSE CODE.
I've done some research and found that a Logarithmic Scale differs from what a normal scales works like where it will increase the X or Y axis in corresponding order such as 1, 2, 3, 4 etc... A logarithmic Scale will take the given number of the X or Y axis and multiply its power to achieve the scales on its axis such as 10, 100, 1000 etc.
More on Logarithmic scales can be found here:
http://en.wikipedia.org/wiki/Logarithmic_scale
As for the Spectrum display or Spectrum Analyser, this device is very similar to an oscilloscope due to the fact that it will measure electric signals but unlike the oscilloscope where that will measure these signals in relative to time, the Spectrum analyser will measure will measure electrical signals that are relative to the frequency of these signals.
More on a spectrum analyser can be found here:
http://en.wikipedia.org/wiki/Spectrum_analyzer