Here's Demetri's breakdown of the passage organization:
Passage A:
Paragraph 1 begins with some background information on the complexity of music. We are told that music should be complicated enough to excite the listener, but not so complicated that it overwhelms. We need something to unify the sound so we can understand it.
Paragraph 2 compares music to language and reiterates the need for a unifying theme in music.
Paragraph 3 provides a deeper analysis of music and emotions by discussing the reactions to different sounds. It tells us that relaxing sounds are continuous and rhythmical while disturbing sounds are discontinuous and erratic.
Passage B:
Paragraph 1 establishes the idea of "musical emotions," which are manipulated by building up and releasing tension in the audience (through creating and satisfying expectations).
Paragraph 2 further explains this idea; positive emotions come when the listener expects something and gets it while negative emotions come when the listener doesn’t get what they are expecting.
Paragraph 3 introduces two new ideas; the first is that familiarity is a factor in our enjoyment of music. We like music more and more as we hear it until we "know" it and then it decreases. Finally, trained listeners prefer more complex music because they can deal with the emotions it produces.