What Is Harmony? How Notes Sound Together, With Examples You Can Play

You can hum a song's tune after one listen, yet at the piano something is missing: the other notes that sound with the tune and give it color and direction. That missing part answers the question what is harmony in music. Melody vs harmony, chords, a sung third and a way to hear it all follow, with notes you can play right now.

What is harmony in music?

Harmony is the sound of two or more different pitches at the same time, and the way those sounds move from one to the next. Wikipedia's article on harmony calls it the concept of combining different sounds to create new, distinct musical ideas. The word comes from the Greek harmonia, "joint, agreement, concord", from a verb meaning to fit together.

The smallest harmony is two notes. Play C and E together on a piano and you hear one sound made of two pitches, a major third. Add G and you have a C major chord, the most familiar harmony in Western music.

Harmony has a vertical and a horizontal side

Harmony works in two directions. The same Wikipedia article describes a "vertical" dimension, the notes stacked at one moment, and a "horizontal" dimension, how those stacks change over time.

The vertical side is the chord: C E G heard at once. The horizontal side is the progression: C major, then F major, then G major, then C major again. When musicians say a song has "rich harmony", they usually mean both: interesting chords and an interesting path through them.

Melody vs harmony vs rhythm

Melody, harmony and rhythm are the three parts most people name when they talk about a song. Each answers a different question, and you can change one while the other two stay the same.

The three parts lean on each other. A melody note that belongs to the chord under it sounds settled, and a note outside the chord sounds like it wants to move. The forum debate on whether music needs melody, harmony and rhythm shows how far you can push one of them before the music changes character.

Two notes are already harmony

Harmony does not need a full chord. A violin and a cello holding two notes, a pianist's left hand playing a bass note under the tune, or two singers a third apart are all harmony.

Three notes stacked in thirds form a triad, the basic chord of most pop, folk and classical music. The guide to triads explained shows how major, minor, diminished and augmented triads are built from those thirds.

Chords and progressions: harmony in motion

A chord progression is harmony moving through time. In the key of C major, you build a chord on each note of the scale by stacking every other note. The three chords that carry most songs are I, IV and V:

• I (C major): C E G, the home chord.
• IV (F major): F A C, a step away from home.
• V (G major): G B D, the chord that pulls back toward home.

Play C E G, then F A C, then G B D, then C E G again, and you have I–IV–V–I. Roman numerals name each chord by its scale degree, so the same pattern in G major is G, C, D, G. The chord progressions guide covers the most common patterns in every key.

The free circle of fifths shows the I, IV and V chords of any key at a glance: IV and V sit on either side of I on the wheel.

Free toolCircle of fifthsKeys, relative minors and key signatures

Consonance, dissonance and the pull of V to I

Consonance and dissonance describe how stable a combination of notes sounds. The Wikipedia article on consonance and dissonance lists unisons, octaves, fifths and fourths as perfect consonances, thirds and sixths as imperfect consonances, and seconds, sevenths and the tritone as dissonances. The same article puts it in one line: consonances are points of arrival and rest, while a dissonance's tension demands onward motion.

That pull drives a progression. The University of Puget Sound's open theory text on harmonic function says the I chord has tonic function, a state of stability and rest, while V tends to progress to I and IV tends to lead to V.

Add F to the G chord and you get G7, G B D F. The B and F form a tritone, the most unstable interval in the key, and they resolve inward: B rises to C, F falls to E. The ending V–I is called an authentic cadence, and IV–I is a plagal cadence, the "Amen" ending of many hymns.

How to hear harmony in a song, step by step

Hearing harmony takes practice because your ear locks onto the melody first. Work through these steps with one song you know well.

1. Pick a song with a clear accompaniment. A piano ballad or a song with one strummed guitar works better than a dense band mix. Fewer instruments leave less to sort out.
2. Hum the melody first. Once you know the tune by heart, you can set it aside and listen to everything else.
3. Follow the bass. The lowest note usually names the chord. When the bass moves, the chord has most likely changed.
4. Count the chord changes. Tap the beat and note where the harmony shifts: once a bar, twice a bar, or every two bars.
5. Label each chord major or minor. Major chords sound bright and open; minor chords sound darker. Write a line of M and m before you worry about names.
6. Find the home chord. The chord that sounds finished at the end of a section is usually I. The guide to finding the key of a song shows how to confirm it.
7. Play it back. Find the bass notes on a keyboard, build a major or minor chord on each, and play along with the recording. The free chord finder names a chord from the keys you press.

ChordIQ trains each of these skills as a game. Major or Minor has you call a chord's quality by ear, Chord Qualities moves on to m7, maj7, sus4 and more, Chord Progressions asks you to pick the Roman-numeral sequence you hear, and Cadences has you name authentic, plagal, half and deceptive endings.

How to describe the harmony you hear

Describing harmony gets easier with a small, fixed set of words. Use them in pairs, and pick one from each pair.

• Consonant or dissonant: do the notes blend, or do they rub?
• Major or minor: does the chord sound bright or dark?
• Tense or resolved: does the moment want to move on, or does it sound finished?
• Thick or thin: are many notes sounding, or two or three?
• Static or moving: does the harmony stay on one chord for bars at a time, or change every beat?

A full description can be one line: "Four major chords, I–IV–V–I, thin piano texture, tense on the V, resolved at the end." That sentence tells another musician almost everything they need to play along.

Harmony in singing: a third above the melody

A sung harmony is a second line that moves with the melody, and the most common one sits a third above it. Take the opening of "Mary Had a Little Lamb" in C major: the melody is E D C D, E E E. Count up three letter names from each note, using only notes of the C major scale, and you get G F E F, G G G.

Sing or play the two lines together and you hear parallel thirds, the sound of countless duets and backing vocals. Thirds and sixths are imperfect consonances, so the lines blend without merging into one sound. Fifths and octaves blend so well that the second part tends to disappear.

Major and minor thirds inside the line

The thirds in a sung harmony change size. Every pair here is a minor third of 3 half steps, E to G or D to F, except C to E, a major third of 4 half steps.

That change keeps both singers inside the key. If you kept every third major, the harmony would sing G sharp over E and F sharp over D, and it would clash with a C major chord. The full method for writing a second part, including when to switch to a sixth below, is in the guide on harmonizing melodies.

A sixth below gives the same note names one octave lower: under the melody note E4, a sixth below is G3. Use it when the third above sits too high for the second singer.

Common harmony mistakes

Most early harmony problems come from hearing only the tune, or from treating every note the same.

• Mistake: confusing the melody with the harmony. The note you sing along to is the melody. Listen below it, starting with the bass, to find the chords.
• Mistake: calling every clash "wrong". Dissonance is part of harmony. A G7 or a suspended chord is tense on purpose, and the release that follows is the point.
• Mistake: using only major thirds in a sung harmony. Fixed major thirds pull the second part out of the key. Count thirds by letter name inside the scale instead.
• Mistake: naming chords from the melody note. A melody E can sit over C major, A minor or E minor. Name the chord from the bass and the full sound.
• Mistake: learning chords without their order. Knowing C, F and G is half the job. Practice them as I–IV–V–I so your ear learns the pull back home.

The edge case: one line can still imply harmony

Harmony does not always need notes at the same time. A broken chord, C then E then G played one by one, outlines C major even though only one note sounds at a time.

Many solo instrument pieces and guitar riffs work this way: a single line jumps between chord tones, and your ear fills in the chords. The deeper theory of why some chords pull toward others is the subject of the post on functional harmony.

Your harmony checklist and next steps

Check these five items with any song you want to understand.

• The melody: you can hum the tune, so you know what to set aside.
• The bass: you can follow the lowest note and hear where it changes.
• The chords: you labeled each chord major or minor and found the home chord.
• The progression: you can write the chords as Roman numerals, such as I–IV–V–I.
• The sung part: you can sing a third above a simple melody and stay in the key.

Piano Companion turns this checklist into practice at the keyboard. Its interactive circle of fifths shows the chords of each key, the progression builder plays your chords back in a loop and suggests relative and common chords, and "Sounds great with" lists companion chords for any chord you pick. On iPhone, iPad and Android, the Progression Library holds 149 progressions in 9 genres with the songs that use them, and MIDI in lets you play a USB or Bluetooth keyboard to look up every chord you find.