Quintal (4 notes)
Q4
0 - 7 - 14 - 21Stacked perfect 5ths (4 notes)
About Quintal (4 notes)
A four-note quintal chord is built from three stacked perfect fifths — in C that is C, G, D and A. Folded into a single octave its notes are C, D, G and A, which is a major pentatonic scale with the third removed: four of the five notes that most folk melody in the world is built from.
Notes and formula
The formula is 0 – 7 – 14 – 21 in semitones: three perfect fifths, spanning two octaves and a fifth.
Continue the stack and the fifth note would be E, completing a major pentatonic. Stopping at four is what keeps the chord free of a third and therefore free of a quality.
The pentatonic connection
A chain of perfect fifths is how pentatonic scales are derived in almost every theory tradition that has one. This chord is four links of that chain sounded together rather than played in sequence.
That is why melodies in a pentatonic scale sit over it without a single wrong note: the chord and the scale come from the same construction.
How to play it
On guitar the shape is x–3–5–x–3–5, sounding C–G–D–A. It is a stretch, and the open-string versions in altered tunings are why the sound belongs to fingerstyle guitar as much as to the orchestra.
On piano the four notes span two octaves and a fifth and are divided between hands, usually with the widest gap at the bottom.
Where you hear it
In orchestral openings, where stacked fifths across the strings establish space before any melody arrives. In minimalism, as a sustained field. In guitar music in DADGAD and other open tunings, where the tuning supplies the chord.
It is also common in game and film music that wants to sound folk-derived without quoting a specific tradition.
Against the three-note version
Two stacked fifths give solidity and space. A third one adds width and starts to suggest a scale rather than a chord, because four notes of a pentatonic chain is enough for the ear to extrapolate the fifth.
That is the practical difference: the smaller chord is a colour, the larger one is nearly a key.
Frequently asked questions
What notes are in a four-note quintal chord on C?
C, G, D and A — three perfect fifths stacked. On guitar, x–3–5–x–3–5.
Why does it sound pentatonic?
Because it is four links of the chain of fifths that generates a pentatonic scale. Add one more fifth and you have the whole scale.
Is it a chord or a scale?
Both, in effect. Sounded together it is a chord; the same notes played in sequence are most of a pentatonic scale, which is why melody and harmony agree so completely over it.