Firstly, let me lay a little musical truth on you. The fundamental idea behind all music is tension and release. The composer builds tension, and then he releases it. This can be accomplished in any number of ways. In its most common form, it comes in the form of dominant sonority to tonic sonority, i.e a V chord to a I chord. This has to do with the resolution of the leading tone (scale degree seven) up to tonic by half-step. However, we can expand this idea as such: harmonically, any dissonance to consonance constitutes a resolution of tension. Any sonority that "rubs" or is "crunchy" or sounds wrong and displeasing to our ears is a dissonance. A consonance, essentially, is the absence of dissonance. So by resolving dissonance, we release HARMONIC tension. HARMONIC tension is the tension that is created or dispelled by the chordal structure of a piece of music. However, tension can be created and released in many other ways. For example, melodic tension could exist by using TENDENCY TONES. Tendency tones are notes that have a TENDENCY to lead to other notes. Scale degree seven to scale degree one (ti-do) is the most common example, but many exist. While we sit on a tendency tone, tension is built. When we resolve, tension is released. We can also use tension in the structure of our piece. We start out with a theme, and then we develop it, giving the listener tastes of that theme, but never fully stating it. This builds tension. The tension is released when we (finally) state the theme again. And finally, one of the most overlooked methods of creating tension is silence. When we come to a dramatic pause in our music, we can almost taste the tension in the air until (phewph) we resume the music and dispel the tension.
Now that you know a little something about the underlying principle of all music, we can start listening for it. Here are some great examples of tension and release, all drawn from some familiar repertoire.
Harmonic Tension- Beethoven, Symphony No. 1, Movement I, the very beginning. Notice how Beethoven starts an entire symphony with the creation and resolution of tension. The first four chords set up, resolve, set up, and then resolve tension.
Melodic Tension- Tchaikovsky- 1812 Overture- The trumpet call. If you don't know what this is, it was on a Subway commercial when a bunch of people's buttons were flying off. The fifth note of this call is a tendency tone, and then is resolved in the final two notes.
Tension in structure- Beethoven, Symphony No. 9 Movement IV. This entire movement is an exercise in tension and release in structure. After an introduction, we hear the famous "Ode to Joy" theme bounce around the orchestra. Then introduction is repeated and the theme moves around a chorus. After a pause (tension through silence), we move through several themes based on the Ode to Joy theme, until it is recapitulated throughout the entire orchestra in truly epic fashion.
Tension through silence- Aaron Copland, Fanfare for the Common Man- the beginning. Here's how this piece starts. BOOOM! (silence) BOOM BOOM! (silence) BOOM! (silence)... you get the idea. Throughout those silences, we have no idea whats going to happen, and therefore, tension is built. It is resolved on the next hit, when we finally understand what is going to happen.
"Well John, these ideas are certainly cool and all, but how do I use tension and release when I compose?"
I'm so glad you asked, inner dialogue. The key to using the principle of tension and release is first understanding it. Hopefully the examples I've given you have aided you in that endeavor. The best thing you can do to further your understanding of this concept is to listen to music. A lot of it. And don't just put it on and go about your business. Really LISTEN to it. If you can, get a score or TAB to go with the recording. Note where the composer has built tension, and where he has released it. Note the methods that he has used as well, and on what scale they are. Is it note to note? Phrase to phrase? Or is it over an entire piece? Most pieces follow this general format.
Tension----------Release Tension-----------Release Tension-----------Release
Tension ---Release Tension--- Release Tension--- Release Tension----Release
Notice how the entire piece usually serves as a buildup of tension to a final release, and then there are smaller sections within the piece that go along with that larger model.
Once you've seen in others how tension and release works, you can start consciously using this principle to enhance your music. The best way to start is by sketching your piece. Note where the big moments are, as these are points at which you'll want to have a resolution. After you've determined where you want to have tension and where you want to release it, the rest is really just a matter of copying what's been done before in interesting and novel ways. If you're really feeling brave, you can attempt to discover a new way to create tension and resolve it, but there are no hard and fast rules for this... you are completely on your own! Think about what type of tension you want: harmonic, melodic, structural, or silence. Remember to pick from all of them, as too much of one eventually becomes static and uninteresting.
Have fun, and happy writing!