Especially since the advent of sequencers and digital audio workstations, an ever-increasing majority of popular music is conceptualized and written in layers. This layered approach to composition is an important structural feature of pop music, deserving of close analytical attention. Allan Moore (2012) observes that traditional terms for describing texture (homophony, heterophony, polyphony, monophony) were developed to describe classical music, and do not offer much insight when applied to pop music. ^[1] He developed the concept of functional layers as a more powerful tool for describing pop textures. Functional layers may be equivalent to a single instrument, or a group of instruments may constitute a single functional layer.

Moore (2012) identifies four functional layers common in pop music:

1. The explicit beat layer
2. The functional bass layer
3. The harmonic filler layer
4. The melodic layer

Lavengood (2020) adds a fifth layer:

5. The novelty layer

While identifying these layers may not seem like a complex task, analyzing the way these layers are constituted is one way of breaking down a song to understand it better, and may furthermore illuminate cultural and generic norms associated with the song.

The concepts in this chapter will be illustrated with the song “3 on E” by Vulfpeck (2020). A list of the instruments that constitute each textural layer is given in Example 1, and the use of the layers throughout the song is diagrammed in a layer graph in Example 2.

Example 1. List of instruments in textural layers in “3 on E” by Vulfpeck (2020).

Example 2. Layer graph of textural layers in “3 on E” by Vulfpeck (2020).

Explicit Beat Layer

This layer “articulates an explicit pattern of beats” (Moore 2012, 20). It is also a key component to establishing the song’s groove, as it establishes and maintains the song’s meter and characteristic rhythms. Instruments in this layer should be unpitched percussion instruments; in much pop music, the drum kit is the instrument that primarily articulates the explicit beat layer, though of course other percussion may be added. The rhythms performed in the explicit beat layer also tend to be regular and repetitive to provide a foundation for the rest of the track, which is more flexible in this regard.

These fundamental properties of the explicit beat layer render it particularly easy to recognize in pop songs. In “3 on E,” the explicit beat layer is present throughout almost the entire track and is played by the drum kit. In the final chorus (2:20), additional auxiliary percussion in the form is added to the explicit beat layer. Example 2 above shows the explicit beat layer with purple.

Functional Bass Layer

Like the explicit beat layer, the functional bass layer is an important component of the song’s groove, and forms part of the foundation of a track. Note that in Example 2 above, the functional bass (shown in blue) is present throughout almost the entire song, like the explicit beat layer. Unlike the explicit beat layer, the functional bass layer also serves an important registral and tonal role: to provide the bass frequency and define the harmonic context of a song. In the vast majority of pop songs, the functional bass layer fills these two roles at once by playing the chord roots on beat 1 of every other measure and/or whenever the chord changes (Example 3).

Example 3. The bass guitar, acting as the functional bass layer, both provides important rhythms to the groove and clarifies the harmony in “3 on E.” Used with permission.

Melodic layer

The principal melodic line(s) of a song form the melodic layer. Of course, the voice is the most typical instrument in the melodic layer, and requires the least theorizing. When other, non-vocal instruments belong to the melodic layer, it is because they carry the melodic line, either alongside or instead of the voice. In Example 2 above, the vocals are a paradigmatic example of the melodic layer (shown in red), and occasionally a brassy FM synth joins the vocals in the melodic layer. As with this brassy synth, instruments in the melodic layer tend to have brighter timbres than those of instruments in other parts of the texture, and moreover, may have a high degree of timbral flexibility that mimics similar changes in the singing voice.

Moore also points out that the instrumentation of the melodic layer is a strong indicator of the genre the song belongs to, and that the melodic layer is usually what listeners remember most clearly about a song.

Harmonic filler layer

Moore says that the harmonic filler layer “fill[s] the ‘registral’ space between the bass and [melodic] layers” (2012, 21). While harmonic filler layers may indeed include mid-range instruments, the presence of scare quotes in Moore’s definition indicates that this is about conceptual registral space, rather than strict frequency-based register. Guitars and keyboardsare most common in the harmonic filler layer (as in “3 on E,” as shown in Example 2 above), but this can vary greatly depending on genre—choirs, orchestras, and horn sections could also be appropriate.^[2]

Novelty layer

The novelty layer functions in opposition to the melodic layer, and is characterized by call-and-response or interjectory gestures and unusual timbres. It is the least essential of all the functional layers discussed in this chapter, and may not be present in every song. Non-standard rock instruments (that is, instruments beyond guitars, drums, and keyboards) and attention-grabbing synthesizer sounds often are used to create a novelty layer.^[3] The ocarinas in the second verse of “3 on E” (0:59) fulfill both the gestural and timbral parameters of this definition, creating a paradigmatic (albeit minimally present) novelty layer (shown in blue in Example 2 above).

Questions to ask while analyzing

As always with music analysis, applying labels is only the beginning of creating a compelling analysis. Following are some ideas for questions to ask yourself to develop your labelling of functional layers into an interpretation of the song based on texture:

• What instruments make up each layer?
• When do layers enter and exit, and how does that relate to the form?
• Are any layers missing altogether? What is the effect of omitting that layer from the song?
• What intertextual associations are implied by the instrumentation of the novelty layer?
• How do the rhythmic profiles of the layers differ?
• Do any instruments participate in multiple functional layers? What is the effect of their change of role?
• How do any of the answers to the questions above relate to genre or cultural context?

• Identifying textural layers (.pdf, .docx). Asks students to access “Going Somewhere” by Akaban on splitter.fm and assign each of the song‘s stems to a functional layer.
• Visualizing texture analysis (.pdf, .docx). Asks students to use Auralayer to map out the instrumentation and texture of “bad guy” by Billie Eilish (2019).