Seventh Chords: Three Flavors, One Extra Note

The short answer: a seventh chord is a triad plus one more every-other-note stack. The three that matter: major 7 (1-3-5-7 — dreamy, jazzy, "Ventura Highway"), minor 7 (1-♭3-5-♭7 — smooth, mellow, all of neo-soul), and dominant 7 (1-3-5-♭7 — restless, bluesy, wants to go somewhere). Learn to hear the three personalities and half of jazz/soul/blues harmony opens up.

The three recipes

Start from C:

Notice the machinery: the third still decides major/minor mood, and now the seventh adds a second axis — natural 7 (a half step under the root: intimate, unresolved-in-a-pretty-way) versus ♭7 (a whole step under: relaxed in minor, itchy in dominant).

The dominant 7 is the fascinating one: major third (bright) plus ♭7 (bluesy) — and between those two notes hides a tritone, the most unstable interval there is. That buried tension is why V7 chords yank so hard toward home (the V7's day job), and why blues — built entirely from dominant 7ths that never resolve — feels perpetually, deliciously unsettled.

Where each one lives

• Maj7 — bossa nova, yacht rock, lo-fi beats, jazz ballads. The sound of "this is nice and we're not in a hurry."
• m7 — funk vamps (usually Dorian ones), R&B, the ii chord in every ii-V-I.
• Dom7 — the blues, period; the V of every key; funk's other favorite. If a chord sounds like it's pointing at something, it's a dominant.

A one-listen ear test: Cmaj7 sounds like a sunset, C7 sounds like someone about to tell you something.

On the fretboard: everything is a small edit

No new territory — seventh chords are barre chords with one finger moved. From the E-shape and A-shape barres:

• E-shape → dom7: lift your pinky (the D-string root doubles as... just lift it — the ♭7 appears on the D string). The classic "blues barre."
• E-shape → maj7 / m7: same D-string note, moved one fret up (maj7) or the minor barre with the pinky lifted (m7).
• A-shape versions: the edit happens on the G string instead.

Then the compact voicings: the four-note shell grips on strings 5-4-3-2 (or 6-4-3-2, Freddie Green style) with root, 3rd, 7th — drop the fifth entirely; it was free from the physics anyway. Shells are how jazz and soul players comp all night without a single full barre.

Practice sequence

1. Hear first: play C → Cmaj7 → C7 → Cm7 on any shapes; name the personality out loud until the labels stick.
2. Edit your barres: run a 12-bar blues converting every chord to dom7 barre edits.
3. The ii-V-I loop: Dm7 → G7 → Cmaj7, all three flavors in one bar-and-a-half of music. This tiny loop is the jazz gateway drug.
4. Arpeggiate them — the four-note arpeggios are next-level soloing vocabulary.