Fundamentals · Lesson 5: Chords — Stacking Notes Into Feelings

In Lesson 4 you learned the secret: the 3rd decides the mood. Now we cash it in. This lesson is where the whole course pays off, because chords are what give music its emotional color — and you already have everything you need to build them.

A chord is simply three or more notes played at the same time. That's it. But which notes you stack determines whether the chord sounds joyful, mournful, tense, or mysterious. And the rule for stacking them is beautifully simple.

#Chords are built by stacking 3rds

Take any note. Skip the next note in the scale, grab the one after. Skip again, grab the next. You've now got three notes spaced a third apart — and that's a triad, the most basic chord (how triads are built).

The three notes have names:

• Root — the bottom note, the one the chord is named after.
• Third — the middle note. This is the mood-decider.
• Fifth — the top note, which adds stability and power.

So a "C chord" is built on the root C, plus the third (E), plus the fifth (G) → C-E-G. Play those three together and you have a C major chord. Notice the fifth (C to G) is that strong, hollow perfect 5th from Lesson 4 — it's the chord's backbone.

#Major vs. minor: one note, total transformation

This is the magic moment the whole course has been building to. Remember a major 3rd is 4 half steps and a minor 3rd is 3 half steps, one key apart. That single half step, applied to the middle note of a chord, flips its entire emotion (major vs minor triads):

Chord	Notes (from C)	Third used	Sounds
C major	C – E – G	Major 3rd (4 half steps)	Happy, bright, resolved
C minor	C – E♭ – G	Minor 3rd (3 half steps)	Sad, dark, serious

Same root. Same fifth. Only the middle note moves down one key, and a triumphant chord becomes a melancholy one. This is one of the most powerful single facts in all of music. Almost everything emotional in harmony traces back to it.

#The other two triads (quick, but worth knowing)

There are two more triad flavors, made by tweaking the fifth as well as the third:

• Diminished — minor 3rd and a flattened (smaller) 5th. Sounds tense, unstable, anxious — like it desperately wants to move somewhere. Great for suspense.
• Augmented — major 3rd and a raised (wider) 5th. Sounds dreamy, unsettled, otherworldly. Rare, but instantly recognizable.

You'll use major and minor 95% of the time. Diminished shows up naturally inside keys (more in Lesson 6); augmented is a special-occasion color.

#Adding the 7th: richer, more grown-up chords

Stack one more third on top of a triad and you get a 7th chord — four notes instead of three. These are the lush, sophisticated chords behind R&B, neo-soul, jazz, and a lot of moody electronic music.

• A major 7th chord (e.g. Cmaj7) sounds dreamy, warm, romantic.
• A minor 7th chord (Cm7) sounds smooth, mellow, thoughtful.
• A dominant 7th chord (C7) sounds bluesy and tense — it has a built-in pull toward resolving somewhere else, which makes it the engine of a lot of progressions.

You don't need to master these now. Just know the principle: keep stacking thirds and chords get richer and more emotionally specific. A plain triad is a primary color; a 7th chord is a shade.

#Why this is the most important lesson

Step back and see what just happened. Every chord — every lush pad, every dark trap progression, every uplifting pop hook — is built from the same move: stack thirds on a root. The mood comes almost entirely from the 3rd. The richness comes from how many thirds you stack. That's the whole system.

This is the moment music theory usually goes from "intimidating" to "oh, that's all it is." Notes → intervals → chords, each built from the one before.

#What you actually need to remember

Idea	The one-line version
Chord / triad	3+ notes together; the basic one is root + 3rd + 5th.
The 3rd	Decides the mood. Major 3rd = happy, minor 3rd = sad.
Major vs minor chord	Same chord, middle note down one key = flips the emotion.
Diminished / augmented	Tense / dreamy — made by also tweaking the 5th.
7th chords	Stack one more third → lush R&B/jazz/soul colors.

You can now build any basic chord and bend its emotion at will. But a single chord is a still photo. Music moves — chords change over time, and the order you put them in tells a story of tension and release. That's the next lesson, and it's where you'll finally see why certain four-chord loops feel so satisfying: Lesson 6: Chord Progressions.

Try it now: play a minor chord, then slide the middle note up one key to hear it turn major. That one move, felt in your own ears, is most of harmony. Open the Studio and do it.