Rhythm is the foundation of almost any song. It provides the skeleton on which all other musical elements are laid. It’s why the drums are (usually) one of the first instruments to be mixed. A good song will have a central rhythm. It is a rhythmic theme that repeats over and over again throughout the song. It is not uncommon to have 2 central rhythmic themes, one for the verses and chorus separately.
The central rhythm of a song can be as important as the vocal hook. It gives a sense of predictability to your song that makes it easy to follow and can be catchy in and of itself. It isn’t necessary for a single instrument to convey the rhythm; the central rhythm can be defined by the interplay of multiple elements in a song.
A great example of this is in The Whistle Song by Flo Rida.
If you listen to the interplay between the drums, the bass synth, and guitars, they form a central rhythm that lasts through the entire record (except a few small sections where the guitars are solo’d). That groove is partially responsible for making the record so catchy.
How does this translate to composition? When I am writing a new instrumental, I may define the central rhythm using a single instrument (guitar, keys, or drums). Either immediately or later in the process, I will split up that rhythm among different instruments to give the track a sense of interplay between the instrumental elements. That rhythm may even vary slightly over the course of the track between sections if variation is called for but it will never stray too far from the central rhythm.
When songwriting, rhythm is equally as important in the topline melody. Frequently we compose the topline melody as a totality of the pitch movements and rhythm. We may even have lyrics already attached to the melody. But this can cloud issues with rhythmic development in the topline.
What is rhythmic development? It is how a rhythm changes as the melody progresses. If it’s exactly the same every bar or every 4 bars, then you have no rhythmic development, which in most (but not all) cases is bad. Your topline ideally needs some variation in rhythm to make it interesting, without changing so much that your audience is lost.
One of my favorite ways of checking the rhythmic development of a topline is to clap it out. Clapping removes all the pitch changes in the melody and gives you sense of what is going on rhythmically. If you clap out your topline and it sounds uninteresting, it may be a problem. Some tracks rely on a repetitive chorus and that may be OK, but in many cases it’s better to have some sort of rhythmic development or, more commonly, a call / response pattern between rhythms.
A great commercial example of rhythmic development is Avril Lavigne’s Smile:
The verses have a strong central rhythm as defined by the drums and electric guitar. Try clapping out the topline in the chorus. You’ll hear how the rhythm evolves in a way that feels natural. The chorus also makes use of rhythmic contrast, where you may have a slower (or less dense) rhythm that progresses into a faster (more dense) rhythm and then potentially back again. It’s another tool for manipulating audience expectation so that your listener isn’t lulled into a slumber.
So, next time you are writing a song, give yourself a round of applause…clap out your topline. It’s like auditioning your song on a different set of speakers. You get that alternate perspective on your work that allows you to fine tune it and take it one step further.