Studying the Music Theory of pop songs on the Billboard Hot 100

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First Inversion in Katy Perry’s This is How We Do
The Seventh Scale Degree in Katy Perry’s Dark Horse
Half Time in Justin Bieber “Beauty and a Beat”
Triplets in Taylor Swift “I Knew You Were Trouble”
A Programming Note from Pop Music Theory

First Inversion in Katy Perry’s This is How We Do

Katy Perry is at it again with another fantastic example of pop music theory. Today’s topic: first inversion.

If you are a songwriter or musician, you absolutely MUST understand first inversion. Let Katy Perry’s simple example enlighten you on this essential music theory topic.

Before we go any further, let’s listen to the song. (You really only need to listen to the first 5 seconds or so)

To keep it nice and easy, Katy decided to put us in the wonderfully simple key of C Major (no sharps or flats).

Listen to the first 4 chords:

A minor (vi chord)

G Major (V chord)

C Major (I chord)* This is our special chord!

F Major (IV chord)

So, what is special about the C Major chord above? The root of the chord is not the C note, but rather E. Another way of understanding this is by looking at the bass line (notes: A-G-E-F).

The C major chord is in what we call first inversion. This is just a fancy way of saying that the lowest note in the chord, the bass note, is not the first scale degree of the chord (C), but rather the third scale degree (E).

The other chords in the chord progression above are in root position, meaning that the bottom note, the root of the chord, is the 1st degree of the chord (the name of the chord itself). There are other types of inversions that occur in pop music as well, which we will cover in future posts.


If you are craving more Katy Perry, she has also taught us about the seventh scale degree and syncopation.  For more on inversions, check out Chromatic Chords in “When I was Your Man” by Bruno Mars.

Can you think of one of the many pop songs that use first inversion? Tell me in the comments!


The Seventh Scale Degree in Katy Perry’s Dark Horse

Last weekend, at a party here in Brooklyn, I discovered that Katy Perry’s “Dark Horse” is a karaoke favorite of mine. Why? Because the chart-topping song (#3 on the Billboard Hot 100 at the time of this writing) is really fun to sing. Also, because the vocal melody is an ideal way to learn about the seventh scale degree.

Dark Horse gives off an evil vibe. This is partly due to the minor key, the pitched down vocals, and the use of tritones (plus the baby crying “Oh No!” at the very beginning doesn’t help). Another contributor to the mood and overall melodic interest of the song is the usage of both types of sevenths.

Let’s start off by listening to our song in question:

Let’s get the nitty-gritty out of the way: There are two types of sevenths commonly used in pop music: the minor seventh (A.K.A. the subtonic) which is a whole-step down from the tonic, as well as the major seventh (A.K.A. the leading tone), which is a half-step down from the tonic. In pop music, either or both sevenths are commonly used in both major or minor keys.

In Dark Horse, we are in the key of B♭ minor (although the So you want to play with magic? section flirts with the relative major key of D♭ major). Our minor seventh scale degree is A♭ and our major seventh scale degree is A♮ (natural).


Now let’s listen for the sevenths in the piece. The minor seventh can be heard in Katy’s very first vocal line (the word “you” in “I knew you were“) as well as throughout the first half of each verse (another example is the next line, the word “you” in “and here you are“).

The major seventh can be heard in the second half of the verse (the “aph” in “Aphrodite” and the word “one” in “Make me your one and only”).

Can you hear it?


Pop Music Theory Katy Perry Dark Horse


It is very important to be able to hear the difference between the major and the minor seventh. Being able to hear the distinction will increase your music listening enjoyment, as well as increase your tonal palette, if you are a songwriter.

Minor sevenths can also be used when you are in a major key. In this case, you would be in the mixolydian mode. An example of this is Lorde’s Royals).

I am a big fan of the minor v chord when you are in a major key (Beyonce’s “God Made you Beautiful” is a great example of that). The minor v is created by lowering (♭) the 3rd of the diatonic major V chord, which is the seventh with respect to the tonic.

Can you think of any other songs which use either major or minor sevenths (or both) in an interesting way? I would love to hear about it in the comments!

Half Time in Justin Bieber “Beauty and a Beat”

Today’s article is an introduction to the music theory topic of half time. Modern pop music, certain styles in particular, utilize and in fact heavily rely upon half time. From Lil Wayne’s “A Milli” to the infamous “Harlem Shake” song by Baauer, half time has infected pop music and the epidemic is reaching almost epic proportions.

Today, we will begin covering the topic of half time with a very basic example of this rhythmic technique. Unlike some of the topics we have covered in the past, half time is a very basic and simple concept to understand and identify.


Half Time Music Theory


For our basic introduction to this topic, we will be using Justin Bieber’s “Beauty and a Beat.” The song was no. 42 on the Billboard Hot 100 Year-End Top 100 Singles of 2013, therefore it qualifies to be written about on Pop Music Theory.

Let’s begin by listening to the song below. You may choose to listen to the complete song, or, if you are in a rush, you may choose to listen to 2 sections indicated below:

  • Regular Time Section: 0:50 – 1:05. (Or, any of the rest of the song, except the half time section.)
  • Half Time Section: 3:05 – 3:35

Justin Bieber’s smash hit is a typical modern pop song complete with bridge featuring currently famous rapper (in this case, Trinidad’s Nicki Minaj). What makes this bridge special? It is in half time relative to the rest of the song.

So, what is half time? Half time is when the tempo and rhythmic feel of a song becomes half the speed it was a moment earlier. Sidenote: When the opposite occurs (tempo and rhythmic feel becomes twice as fast), it is called double time.


One very common way of indicating tempo and rhythmic feel in pop music is by the pulse of the snare and kick. Using the snare as an example, half time occurs when the same unit of time which contained 2 tempo-producing snare hits, now contains 1. It is very important to note however, that many modern pop songs no longer use snare drum to indicate tempo, meter or rhythmic feel (see my last post for an example).

For a helpful clarification, please watch this brief YouTube clip for an example of half time (watch from 0:06 – 0:46).

At this point, you should be able to hear the difference between regular time and half time (the half time sounds half the speed). Go back above and listen to “Beauty and a Beat” again. When Nicki Minaj comes in at 3:05, the song goes into half time for the next 30 seconds.

This simple rhythmic technique has massively affected modern pop music, an explanation of which is beyond the scope of this introductory article. I will be continuing to go into greater detail about the concept of half time, and I will be reporting many further examples. If you are eager for another read now, please see my last post on a Taylor Swift song that utilizes half time during the chorus:

Triplets in Taylor Swift “I Knew You Were Trouble”

Thanks for reading. Let me know what you think. I’ll see you in the comments below!

Triplets in Taylor Swift “I Knew You Were Trouble”

Today we will be covering the role of triplets in Taylor Swift’s “I Knew You Were Trouble.”

Taylor Swift is riding high on the Billboard Hot 100 Year-End Top 100 Singles of 2013 with her smash hit “I Knew You Were Trouble.” The track came in at number 16 on Billboard’s year-end wrap up, the highest showing of any Taylor Swift song for this year.


Pop Music Theory - Triplets in Taylor Swift by Eric Strom


From a music theory point of view, the song has several noteworthy features. It utilizes relative key, as it alternates back and forth between F♯ Major and D♯ Minor. The meter of the song utilizes half time, a technique which is extremely popular in current pop music, and a topic upon which I will be publishing a complete blog post soon. The verse uses what I refer to as the golden chord progression. Most importantly, the song uses a prominently placed triplet for rhythmic interest in the chorus. This is what we will be focusing on for this blog post.

Before we begin our discussion of triplets, I would like to draw your attention to the chorus of the piece, which occurs at 3:08 – 3:21. Please listen to this section, which is queued up in the video below.

Can you hear the triplet? Below is a notation of the synth keyboard chords from 3:08 – 3:15. As you can see, the triplet occurs in the fourth measure. (Side note: The section is notated in F♯ Major, however the tonal center at this point in the piece is D♯ Minor. These two keys are relative and thus they effectively share the same key signature)

So, what is a triplet? A triplet is when a chunk of musical time is divided into three equal rhythmic stresses. In this case, the duration of our triplet is equal to two of the original quarter note values contained within. The triplet, which is a strong deviation from other rhythmic patterns found in the work, adds rhythmic interest.

Pop Music Theory - Triplets in Taylor Swift by Eric Strom

There is no doubt that this triplet, along with the syncopated eighth note chords, reflect the infusion of a modern genre of music called dubstep. These rhythmic techniques, in particular the jarring triplet, go a long way in characterizing the feel of this section.


This stylized technique takes away from the timelessness of the record, and will make the work sound dated a decade or two from now. Nevertheless, the purpose of this blog is to analyze the music theory of pop songs that are currently on the Billboard Hot 100, and to do that while ignoring the widespread prevalence of dubstep-inspired triplets would be impossible. Listen to the synth in the opening verse of Imagine Dragon’s “Radioactive” below for another example.

Thank you for reading today’s post about triplets. Can you think of any other modern pop songs that use triplets? Please leave me a comment below!

Like this article? You may also enjoy Taylor Swift’s use of Polyrhythm in her song “22.”

A Programming Note from Pop Music Theory

Exactly two months ago, I started this blog, which is called Pop Music Theory (PMT for short). During that time, I have analyzed the music theory of 11 pop songs. Although this blog is still in it’s infancy, I am proud to say that PMT has received over 700 unique views! I am so grateful to each and every person who took the time to read my blog.

Most of the songs that I have covered to date have been songs which are currently on the Billboard Hot 100, which is the American music industry standard pop chart. However, we have also covered a more diverse range of songs, including unreleased/leaked pop songs and classic David Bowie. This has given me the freedom to write about any song I choose.

However, freedom is not always a good thing. With this in mind, I have decided to restrict myself to only analyzing songs which are, at the time of writing, on the Billboard Hot 100. Like the 140 character limit of Twitter, restriction leads to creativity. Also, restricting myself in this way will help remove any bias I may have towards certain musical devices which, given access to the entire library of popular music, I would be able to selectively highlight.

To keep consistent with this decision, I have eliminated the “Classics” and “Can you Hear It?” categories on this website. I have also unpublished the analyses of songs which are not on the Billboard Hot 100.

I believe that this decision will give this blog a more focused goal and story. Although my decision is final, I would very much like to hear any feedback, questions, concerns or commentary that you may have. Please leave a comment below, and thank you again for reading Pop Music Theory!

Copyright © 2014 Eric Strom