Buildups often require particular attention when composing. A buildup section is one immediately leading up to a point of high energy. Commonly this is the climax of the song – the most important part of the song. The buildup is critical because it has to lead up to the climax in a way that maximises its effect. This is best done by enhancing the listener’s sense of anticipation and expectation.
I’ve written about expectation in this post, but that alone is not enough. For a stronger effect, also consider sequences, precedent, linear movement and transition.
Sequences are repeated patterns in music. As explained in the post on expectation, sequences play an important role in setting the listener’s expectations. Worth considering, though, is using sequences at different levels. For example, you could use repeated patterns within the buildup to create a cyclic effect.
Precedent applies this idea to a wider scope – whole sections. You could also make the buildup itself part of a larger sequence. By having a smaller buildup leading up to a smaller climax earlier in the song, you heighten the listener’s expectation of a bigger climax at the end of a bigger buildup.
Linear movement is important in a buildup. Many song sections are static – they stay the same throughout the section (the same level of energy, the same types of sounds, the same density, etc). The buildup, however, works best if it is in motion. Typically, this works best if the buildup is gradually getting louder, more energetic and more complex. The buildup section might start quite subdued and understated, but at the end it might have enough energy to meet the climactic next section.
Transition is related to linear movement. It might help to think of the buildup as a transition section between the climax and whatever precedes the climax. Using the buildup as a transition section also helps glue the song together because it links the two adjacent sections (rather than sounding as a separate section on its own).
Another useful technique is to introduce a short “gap” in between the end of the buildup and the beginning of the climax. As explained in the last section of the post on expectation, this pushes back the climax and increases the sense of expectation and anticipation in the listener.