Intensity Changes
The energy and emotion within a song can be called its INTENSITY. As a song progresses, the intensity will change, depending on various aspects of the musical content. We ‘feel’ intensity, just as a conversation with someone can go from being relaxed to passionate, or a story can swing from comfortable to terrifying.
What are the musical factors that affect a song’s changing intensity?
Number of instruments – tempo – number of notes per bar – dynamics – tonal effects – attack – rhythms (simple or complicated) – performance style/lyrics – harmony – pitch range/variety
Here’s a rough graph of the intensity changes in Teen Spirit.

What do we do with the information?
Understand dynamics – knowledge to control music to communicate – construct arrangements effectively – relate music to emotion.