Seventh Chords and Extended Chords

Let's start by listening to two loops. They're the same four chords from C major, F, Em, Dm and C, played twice. In the second version, we simply added one note to each chord.

And here's the same progression, with one more note in each chord.

You heard it: the second version is softer, warmer, a little nostalgic. It's a sound you'll find in a lot of lo-fi and deep house. It all comes from a single idea you already know: keep stacking thirds.

One more third: the seventh chord

Take a triad and add a third above its fifth. The new note sits a seventh above the root, which is where the name seventh chord comes from. Since the starting triad and the added seventh can each take several forms, you get several types of chords. Five of them are enough for almost all the music you produce.

Read the table row by row. The maj7 is a major chord with a major seventh, a half step below the octave: that rub, softened by the distance, gives it its dreamy color. The m7 is a minor chord with a minor seventh: dark but never harsh, it's everywhere in house and lo-fi. The plain 7, which is called the dominant seventh, is a major chord with a minor seventh. It contains a tritone, between its third and its seventh, and that's why it sounds tense.

The last two are less common. The half-diminished chord, written m7♭5 or ø, is a diminished chord with a minor seventh; it appears naturally on the seventh degree of the major scale and on the second degree of minor. The diminished seventh stacks three minor thirds: all its notes are three half steps apart, which makes it very tense and a little theatrical. In theory, its seventh is spelled B𝄫, B double flat, but on the grid it's simply the A row. Listen to all five on the same root.

These five colors become fairly easy to tell apart by ear, as long as you practice regularly. Start with maj7, m7 and 7, the most useful ones, then add the other two once you stop making mistakes.

The sevenths of a key

Just as with triads, you can harmonize a scale in seventh chords, staying on its notes. In C major, you get Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7♭5. In A natural minor, you find the same chords in a different order: Am7, Bm7♭5, Cmaj7, Dm7, Em7, Fmaj7 and G7. With the G♯ from harmonic minor, the fifth degree becomes E7, and the seventh becomes G#°7, the diminished seventh chord.

That's good news: to enrich a loop, you don't need to change chords. Add to each one the seventh the scale gives it, by continuing to take every other highlighted row above the fifth, and the chord stays in the key. That's exactly what we did in the loop at the start.

Ninths, elevenths, thirteenths

You can keep stacking beyond the octave. A third above the seventh gives you the ninth, which is simply the second note of the scale, an octave higher. One more third, and it's the eleventh, the fourth note an octave higher. One more, and it's the thirteenth, the sixth note an octave higher. After that, you'd land back on the root: all seven notes of the scale would be in the chord.

The symbols follow a precise logic. Cadd9 adds only the ninth, D, to the C major chord, with no seventh. C9, on the other hand, implies the dominant seventh: C, E, G, B♭ and D. For a ninth with a major seventh, you write Cmaj9; on a minor chord, Cm9. In the same way, C11 and C13 imply the seventh and, in principle, the levels in between. So the word “add” is the key: it signals a note added without the levels below it.

Here's a chord you often hear in house and neo-soul, D minor ninth, Dm9, with its five notes.

Listen to how soft it is. The ninth, E, rubs slightly against the root D and against the third F, but because the notes are spread apart, the rub becomes a color. Minor ninth and eleventh chords are common in deep house, R&B and neo-soul; lo-fi loves maj7 and m9 chords; liquid drum and bass often uses maj7 chords and ninths for their brightness. These are tendencies, not rules.

Which notes to leave out

A chord with five, six or seven notes quickly gets too crowded, especially with a bass and a melody around it. So you leave notes out, almost always in the same order. The fifth is the least useful note: it says neither major nor minor and blends into the rest, so it's the first to go. The root can go next if the bass is already playing it. On the other hand, almost always keep the third and the seventh: they're the notes that define the type of chord.

The eleventh calls for some care. On a major chord, it falls a half step above the third, an octave higher, and that rub generally sounds bad. So in a C11, the third is often left out, and in a C13, the eleventh is usually left out. On a minor chord, this problem doesn't exist, because the eleventh sits a whole step above the minor third: an m11 sounds great with all its notes, or nearly all. Listen to the difference between an Am9 stacked as is in the low end and the same chord thinned out.

The second version sounds clearer and more modern, even though it has one note fewer and its notes are further apart. Notice, too, that the top three notes, C, G and B, look like a Cmaj7 without its third: many rich chords are really a simpler chord sitting on a different bass note.

With all these symbols, chord names become a little language of their own. The last lesson in this part teaches you to read and write it without hesitating.