Notes, Intervals and the Piano Roll

Western music uses twelve notes, repeating in every octave:

C, C♯/D♭, D, D♯/E♭, E, F, F♯/G♭, G, G♯/A♭, A, A♯/B♭, B — then C again.

The distance between neighbouring notes is a semitone (half step). Two semitones make a tone (whole step). On a piano keyboard, the white keys are the natural notes and the black keys are the sharps and flats. Note the two places with no black key between white keys: E–F and B–C are only a semitone apart.

The piano roll is a keyboard on its side

In a DAW's piano roll, each horizontal row is one semitone, with a keyboard drawn down the left edge. Move a note up one row and it rises a semitone; up twelve rows and it's the same note an octave higher.

This is the producer's big advantage over sheet music: you can do theory by counting rows. You don't need to know that a chord is "F♯ minor" to build it — you need to know the shape, measured in semitones.

Intervals

An interval is the distance between two notes. Each one has a name, a size in semitones and a character:

Semitones	Interval	Example from C	Character
0	Unison	C	Same note
1	Minor 2nd	D♭	Tense, clashing
2	Major 2nd	D	Step, open
3	Minor 3rd	E♭	Sad, dark — defines minor
4	Major 3rd	E	Bright, happy — defines major
5	Perfect 4th	F	Open, suspended
6	Tritone	F♯	Unstable, wants to resolve
7	Perfect 5th	G	Strong, stable — power chords
8	Minor 6th	A♭	Bittersweet
9	Major 6th	A	Warm, sweet
10	Minor 7th	B♭	Bluesy, unresolved
11	Major 7th	B	Dreamy, lush
12	Octave	C	Same note, higher

Two to memorise first: 3 semitones (minor third) and 4 semitones (major third). The difference between them is the difference between a sad chord and a happy one.

Octaves and register

The same note in different octaves does different jobs. Rough working ranges:

• C1–C2 (about 33–65 Hz) — sub bass and 808s.
• C2–C3 — bass lines.
• C3–C5 — chords, keys, pads.
• C4–C6 — melodies, leads, vocals.
• Above C6 — sparkle, bells, arps.

Note naming varies by DAW: middle C (MIDI note 60) is called C3 in some and C4 in others. Check yours before following a tutorial's octave numbers.

Consonance and dissonance

Intervals sit on a spectrum from stable (consonant) to tense (dissonant):

• Most stable: unison, octave, perfect 5th, perfect 4th.
• Sweet: major and minor 3rds and 6ths.
• Tense: major and minor 2nds and 7ths, the tritone.

Dissonance isn't wrong — it's tension. Music works by creating tension and resolving it. A minor 2nd held in a pad sounds harsh; the same minor 2nd as a passing note in a melody sounds expressive.

One practical warning: intervals get muddier the lower they are. A major third at C4 is clear; the same third at C1 is a growl of beating frequencies. That's why bass parts mostly play single notes, octaves and fifths, and chords live higher up.

Exercise: build by counting

In an empty piano roll, starting from any note:

1. Place a note, then another 4 rows up, then another 3 rows above that. That's a major chord.
2. Move the middle note down one row. Now it's minor.
3. Play the bottom and top notes alone: a perfect 5th, the power chord.

You've just built chords without naming a single note.