What Notes Sound Good Together? A Beginner's No-Clash Guide

Notes sound good together when they sit a third, fourth, fifth, sixth or octave apart, such as C with E or C with G. Those pairs vibrate at simple frequency ratios (the fifth is 3:2, the major third 5:4), so their overtones line up and blend. Notes one semitone apart, like E and F, clash, and the tritone (C with F#) sounds tense. The reliable method: pick one scale, stack every other note of it (C E G, A C E), and listen for half steps.

Why do some notes sound good together and some don’t?

Every note an instrument plays is a stack of frequencies. A3 on a piano vibrates at 220 Hz, and above that fundamental it also sounds quieter harmonics at 440, 660, 880, 1,100 and 1,320 Hz, each a whole-number multiple of the first.

Now add E4, about 330 Hz. Its harmonics sit at 660, 990 and 1,320 Hz. Two of them land right on harmonics of the A, so the two notes share part of their sound and blend smoothly. That pair is a perfect fifth, a 3:2 ratio, and it is the most stable interval after the octave.

Play E4 and F4 together instead. They vibrate at 329.6 Hz and 349.2 Hz, about 20 Hz apart. Two frequencies that close drift in and out of step, and you hear the combined sound pulse about 20 times a second, faster still in the harmonics. The ear reads that pulsing as roughness. Musicians call it dissonance, and the half step (one semitone, the smallest step on a piano) is the roughest interval in Western music.

The simpler the ratio, the more harmonics line up: octave 2:1, fifth 3:2, fourth 4:3, major third 5:4, minor third 6:5. In pure tuning the half step works out to 16:15 and the tritone to 45:32, so almost none of their strong low harmonics meet. A piano in equal temperament bends the sweet ratios slightly: its fifth is 2 cents flat of a pure 3:2 and its major third about 14 cents wide (a cent is a hundredth of a semitone), and the ear accepts both.

Two things change how rough any pair sounds:

• Register. The same interval gets muddier lower down, because the notes crowd closer together in hertz. C4 and E4 are 68 Hz apart, while C2 and E2 are only 17 Hz apart. As a rule of thumb, keep thirds at C3 (the C below middle C) or higher, and give the bass octaves and fifths.
• Tone. A pure sine wave has no overtones, so two sines only rub when the notes are very close. A bright saw wave or a distorted guitar is packed with harmonics, and every clash gets louder. That is why rock guitarists play power chords (root and fifth) through heavy distortion: a third turns to fizz.

Part of it is learned, too. In a 2016 study published in Nature, MIT’s Josh McDermott and colleagues found that members of the Tsimane’ people in the Bolivian Amazon, who had heard very little Western music, rated consonant and dissonant chords about equally pleasant, while American listeners strongly preferred the consonant ones (MIT News write-up). So the physics explains which pairs rub, and your listening history decides how much you mind.

What two notes sound good together? Intervals by ear

The distance between two notes is an interval, counted in semitones: one semitone is one key to the very next key on a piano, black or white. Here are all 12 intervals inside an octave, measured up from C and sorted roughly from smoothest to harshest.

Try it on any keyboard. Hold middle C (C4) with your left thumb, then play each note from the table above it with your right hand, holding both for two seconds. The octave and the fifth sound almost still. The thirds and sixths shimmer faintly but stay sweet. The seconds and sevenths rub, and the minor second buzzes.

That gives you three groups to remember:

• Stable: octaves, fifths and fourths. They carry no major or minor flavor, which is why bass lines, drones and power chords lean on them. The fourth is the least settled of the three: held over a bass note, it wants to fall to the third.
• Sweet: thirds and sixths. They carry the mood, major for bright and minor for dark. Two singers holding a line a third apart is the classic harmony vocal.
• Color and tension: seconds, sevenths and the tritone. These make a chord interesting, and they are the notes that want to move somewhere next.

Notes that sound good together on piano

The white keys are the scale of C major, and they give you the easiest rule on the instrument: play every other white key. Skipping one key always lands you a third higher, so C E G, F A C and A C E are all triads, three-note chords made of two stacked thirds. Start the pattern on each white key and you get the seven chords of the key:

B diminished is the odd one out. B to F is a tritone, so that chord sounds tense and unfinished. The other six all sound settled, and you can hear them as full chords on the free online chord player by picking C major.

The clashes on the white keys are the neighbors. C and D, D and E, F and G, G and A, A and B are whole steps with a black key between them, a gentle rub. E and F, and B and C, have no black key between them, so they are half steps, and together they buzz. Play E with F, then E with G, and you will hear the buzz switch off.

The five black keys make a pentatonic scale of their own: F# G# A# C# D#. No two of them are a half step apart, and none form a tritone, so any handful of black keys sounds fine together. It is a good place to let a kid (or yourself) improvise without a single sour note.

Spacing matters as much as which keys you press. C4 with B4 above it rubs. Play C3 in your left hand and B4 in your right, and the same two letters sound lush: that is the top and bottom of a spread-out Cmaj7. Most clashing pairs soften as you pull them apart. The exception is the minor second: stretched into a minor ninth (C3 with Db4), it still stings. Low down the problem flips: C2 with E2 in the left hand sounds like mud, so play C2 with C3 or G2 and let the right hand carry the E.

When clashing notes sound good: tension and release

A clash is a sound that has not finished. Music uses that pull all the time, and the trick is to move the clashing note before the ear gets tired of it.

The textbook case is G7 going to C. G7 is G B D F, and B and F inside it are a tritone apart. When the chord changes to C, B steps up a half step to C and F steps down a half step to E. The tension lets go, and the ending feels like coming home. Play G B D F, then C E G, on any keyboard and follow the B and the F with your ear.

Sus chords work the same way on a smaller scale. Csus4 is C F G, and the F sits a half step above the E it replaces. Hold it for a beat and drop the F to E, and the chord sighs into place.

The rule of thumb for melodies: a clash that passes by is spice, and a clash you hold is a problem. A quick F on the way from G down to E over a C chord sounds fine. Hold that F for a whole bar and it grinds against the chord’s E.

How to always know what notes sound good together

Four habits cover almost every case.

1. Pick a key and stay in it. The seven notes of a major scale mostly get along. In C major the only pairs that clash or pull are E with F, B with C, and B with F.
2. Drop to the pentatonic for melodies. Take the 4th and 7th out of a major scale (F and B in C major) and both half steps and the tritone go with them. What is left, C D E G A, is the major pentatonic scale, five notes with nothing a half step from anything else (why the pentatonic scale has no wrong notes). On a phone, the Notes mode in Gelato Synth does this for you: pick a root and a scale, and the pads show only those notes, three rows for three octaves. Set it to Major Pentatonic and there is no half step anywhere on the screen.
3. Land on chord tones. When a melody note is held over a chord, make it a note of that chord: C, E or G over C major; A, C or E over A minor. Other notes are fine in passing. There is more on this in how to write a melody over chords.
4. Check held notes for half steps. If a long note sits a half step above a chord note, move the note a step or change the chord. A C held over E minor rubs against the B; put A minor under it instead and the C becomes a chord tone.