Student or Learner
Rock 'N' Roll is particular to this period of time. There was no precedent in musical history because it is completely about electricity.
--- I'm not sure I understand the part about electricity? Can you rephrase it, if it's possible?
The next sentence is: When you play an electric guitar through a Marshall amplifier in a studio with the volume turned up so loud it reaches the point where it has stopped being able to accurately reproduce the sound, you create the effect of compression.
Rock 'n' roll came into being at the time when musical instruments could be powered by electricity for the first time, allowing musicians to create sounds that cannot be created on a normal instrument [apart, probably, from the pipe organ].