Root position
The root lies in the bass — the most stable position of a chord.
What it means
A chord is in root position when its root is the lowest sounding note. This is the most stable position: the root carries the sound, and the other notes arrange themselves above it as corresponds to the harmonic series. Which note lies on top plays no role for this — decisive is the bass alone.
In the notation
In figured-bass notation, the triad in root position receives no figure; the absence of an indication thus means root position. The seventh chord in root position is figured with 7. In degree and function labelling, root position appears without addition, whereas inversions are indicated separately.
Musical use
Because of its stability, root position is the position for endings. The perfect cadence demands that dominant and tonic stand in root position, with the root in the bass and the tonic in the upper voice; only then does the ending seem complete. Beginnings of sections also often stand in root position.
In the course of a movement, by contrast, a sequence of nothing but root positions would sound heavy and leaping, because the bass would then always carry the roots and move in large intervals. Inversions allow a bass that strides instead of leaping, and connect the sonorities more smoothly. The art of writing lies in the alternation.
In four-part writing in root position the root is as a rule doubled, because it supports the sound most firmly.
Root position is to be distinguished from close or open position, which concerns the distribution of the upper voices and is independent of it.
Root position is the rule at the end of cadences, because it produces the strongest conclusion. Inversions, by contrast, lead on and make the bass part melodic. In figured bass, root position has no figure or a 5/3, inversions the corresponding figuring.
Performance practice
Give the root in the bass weight, especially at endings — it carries the calm of the sound. Listen by comparison to how the same chord acts in root position and in inversion. And, when harmonizing yourself, take care to save root positions for goal points.