Seventh Chords

1. Seventh Chords

In the episode Prime Chords (1), we discussed the stacking of notes. In that discussion, we briefly touched on jazz theory, which often uses chords based on stacking four notes.

The fourth note added on top of Rt3^rd5^th becomes the “7th” interval, hence referred to as 7th. Chords with a 7^th interval are collectively termed as Seventh Chords. Even with the addition of the seventh, the fundamental sound of the major/minor chords remains unchanged.

In the article Seventh and Tension Chords I mentioned that adding 7^th is the most user-friendly approach to add extra notes to triads, so you may have already put this into practice. In this session, I will formally explain it, including detailed information like chord names and chord symbols.

Listening Comparison

Let’s start with a pure listening comparison between regular triads and seventh chords.

Triads

The chord progression is IVIII_mVI_mIIII_m. All made with triads so it has clear and straightforward sound. Let’s change all of these to seventh chords.

Seventh Chords

Just adding one note make the track considerably more complex! This is the power of seventh chords.

Seventh chords are characterized by simultaneously sounding adjacent notes in a scale. For exaample, it is B that becomes the 7^th of a C chord. Regardless of their octave positions, B and C create dissonance. But the “dissonance” here is a beneficial element, since a certain degree of tonal complexity adds depth and richness to music. Their dissonance is a modest level and still have good stability due to its consistent 3rd intervalic structure.

Voicings

Depending on the voicing (where you place the 7^th note), a seventh chord can achieve slightly different impressions. It stands out when 7^th is at the top, or it blends in the chord when placed in the middle.

Piano and Seventh Chords

By effectively using seventh chords, you can make your music distinctive.

Triads

A chord progression repeating IV and I. It may seem like a simple piano piece, but when you change it to seventh chords and adjust the melody accordingly…

Seventh Chords

This is…!! It has become Erik Satie’s “Gymnopédie No. 1.” This piece actually fully utilizes the charm of seventh chords. Seventh chords have the power to make a piece beautiful and attractive simply due to their exquisite tonal complexity.

Guitar and Seventh Chords

Even in genres like guitar rock, seventh chords can be utilized.

Triads

This is a triad version. The sound is simple and not much characteristic in current state. Let’s try changing it to seventh chords and see how much the sound changes.

Seventh Chords

This time, the central guitar consistently emphasizes the 7^th note on top and 3 guitars come together to construct the seventh chord harmony.

With the added complexity, it becomes more intricate and mature! What’s amazing is that just by mechanically adding 7^th, it somehow feels like it has a kind of “message”. The complex sound of Seventh Chords seems to have a captivating appeal that resonates with our hearts.

Simple or Complex

However, using Seventh Chords exclusively can reduce the variation in the overall harmonic density of a piece, potentially causing the song to sound less dynamic. It’s important to carefully discern where to add complexity and where to keep it simple to create good variety in sounds.

This is another sample where I intentionally simplified the ending part with guitar&bass unison.　Suddenly reducing the number of notes can create a surprise effect. Additionally, the introduction of simple chords makes it more evident that the chords in the first half were complex. The contrast between lavish and modest elements is crucial in music, which is true to various aspects of music such as timbre, rhythm, or melody.

So, it might be a good idea to envision an image like below.

Just like nexuses, the likings for chord complexity vary greatly depending on genres. Classical music is based on triads and there are some “regulations” for the usage of seventh chords. Modern jazz, on the other hand, is totaly based on seventh chords so using triads is even seen as an exceptional choice deliberately avoiding the use of sevenths. Rock-oriented genres tend to use simpler forms like triads or power chords, while jazz-oriented genres loves seventh chords, etc.

Therefore, it is desirable to consider the complexity of chords from two perspectives: the dynamics of music and the styles of genres.