Contents
3. Characteristics of Each Nexus
2nd Nexus
The 2▲2▼ progression involves moving to an adjacent chord, creating a very gentle and smooth impression for listeners. While there are two “former prohibitions” in 2▼, they are prevalently used in current music without much concern, probably due to its smoothness of connection.
Hence, you can remember all of them as “connecting smoothly and creating a serene musical atmosphere.”
5th Nexus
Skipping 3rd nexus and let’s inspect 5th nexus first. In contrast to the 2nd nexus, the large leap in root movement makes it sound dynamic, as we discussed last time. Comparing ascend and descend, there’s one “formerly forbidden” nexus in 5▲, whereas there are none for 5▼. This is where a notable difference emerges, unlike 2nd nexus.
5▼ is More Traditional
For instance, jazz is known for its preference for 5▼ over 5▲, and there are even books suggesting that a large portion of jazz progressions are based on this type of movement1.
- 2-5-1-4-2-5-3-6
Here is an actual chord progression constructed largely with 5▼, getting well with the style of jazz. Even in classical music, the viewpoint of using 5▼ as the fundamental progression is often observed. Especially in the context of reaching the tonic, I chord, V→I has much more importance than IV→I.
Thus, the two major Western music theory genres, classical and jazz, both prioritize 5▼ over 5▲.
Rock : The Rebellious Spirit
Conversely, avoiding 5▼ can work as a departure from the classical/jazz style. In fact, in rock, US pop or EDM, there are many popular progressions using 5▲.
“Radio” by Lana Del Rey uses 4-1-5-2 loop, which is entirely composed of 5▲ nexus. Observe that this is a total reversal the jazz standard “2-5-1-4” introduced earlier!
Such frequent usage of 5▲ in rock is pointed out even in a theory book2. Differentiating these nexuses is important in designing the taste of genres, as well as pure musical expressions.
How to Remember
5▲ and 5▼ are like two sides of a coin, completely opposite in nature. Given that the progressions move in total opposite directions, it’s quite natural. When trying to remember which is which, it’s helpful to imagine that “going down feels natural and easy, while going up requires power and a rebellious spirit.”
Although this is purely imagery, classical music theory books sometimes refer to chord progressions that involve a sequence of 5▼ as a “waterfall of fifths,” reinforcing the concept that “falling down 5th from above is natural.”3
3rd Nexus
The 3rd nexus plays a slightly supportive role compared to the previous two. This is because they don’t occur when connecting a major chord to another major chord like I–IV–V or minor to minor like VIm–IIm–IIIm.
In fundamental chord progressions like “1-4-5-1” or “6-2-3-6,” forming the basis for major and minor keys, 3rd nexuses are not involved. Consequently, the primary role that 3rd nexuses play is bridging between major and minor chords, such as I⇄VIm, IV⇄IIm, V⇄IIIm.
As you can see, within the range of the six prime chords, 3rd nexuses always result in a major/minor inversion.
Many Prohibitions in 3rd Up
Remarkably, most of the 3▲ connections are formerly considered as “prohibited”. In classical and jazz music, these connections are used less frequently compared to other nexuses. However, they have gained traction in recent popular music genres like rock, techno, EDM, and hip-hop. They are like emerging forces these days.
The chorus part of “Wonderwall” by Oasis uses mostly 3▲, namely, the “4-6-1-6” progression. “Get Lucky” is also based on the 3▲ progression, “2-4-6-5.” These progressions offer a unique sensation of floating, different from the “smooth neighboring 2nds” or “the dynamic leaps of 5ths”. Although not favored in classical/jazz, they should be considered as one of the expressive tools in the palette of popular music.
On the other hand, 3▼ nexuses are in general versatile and used across genres, but they also contain one connection that requires special attention.
How to Remember
For these 3▲ and 3▼ nexuses, you can remember them in a similar approach as 5▲5▼ : imagine that “falling down is natural and easy, going up is tough.”
To summarize roughly, “2nds are smooth and can fit into anything, 3rds and 5ths often flow better in descending motion, while ascending motion tends to have more quirks.” Classical and jazz prefer natural progressions, while recent popular music uses different approaches to create new sounds…
With this, we’ve established another criterion alongside TDS chord functions. How to skillfully use the “former prohibitions” will be detailedly explained in subsequent individual articles.
4. Common Tones and Changes in Sound
When connecting chords, it frequently happens that the chord tones are shared between the preceding and following chords, and this is referred to as a Common Tone.
In the connections of prime chords, the number of common tones depends on the interval of the nexus.
2nd : No Common Tones
When connected in 2nd, there are no common tones. This is because 2nd nexuses involve moving to the adjacent chord, resulting in a complete change of the members.
So, 2▲2▼ have duality—small changes in root motion, big changes in chord tones. It may be an abstract explanation but they bring significant changes to the “color” of harmony4.
5th：1 Common Tone
When connected in fifth, there’s always 1 common tone.
In other words, this means that 2 out of 3 tones are changed. Adding the fact that the root motion is large, 5▲5▼ indeed produce a power and propulsion on its connection.
3rd：2 Common Tones
3rd nexuses have the most common tones, with 2 of the 3 tones remaining the same.
So, while 3rd nexuses have larger root motion compared to 2nd nexuses, they may give a slightly flatter and less progressive impression when compared to the 2nd nexuses, which involves the total exchange of chord tones.
Considering this, it can be said that only 5▲5▼ can distinctly drive forward the development of music.
By analyzing chord progressions from the viewpoint of root movement, we have gained a more detailed understanding of their characteristics. It might have been quite surprising to discover that different genres have different likings regarding root motion.
In the upcoming sessions, we’ll delve into each type of connection with detailed examples to provide further explanations.
Summary
- We’ll classify chord progressions based on the amount of root movement between 2 chords.
- This approach not only helps us understand the musical expressions but also reveals genre-specific preferences.
- Root motion is closely related to the number of common tones, which is another significant viewpoint in analysis.
