It isn't necessary to have a specialized knowledge of, say, the intricacies of counterpoint, or even to be able to read music to understand it. Usually, getting the point of a piece of music, its emotional and dramatic impact, is immediate or simply requires you to become more familiar with it. Of course, prolonged study of music and its composition, as in any other field, will increase your understanding, but not necessarily your enjoyment. Now, I realize that it can require a good deal of willingness on our part to risk new sensations, and there is a lot of music that will seem unfamiliar and alien to you on a first hearing.