The SATB Texture

Introduction: The Illusion of Chords

So far we've stacked triads like blocks. But music isn't a series of disconnected vertical blocks. When a choir sings a chord progression, the audience hears harmony, but the singers don't: the sopranos are thinking only about their melody, and the basses only about their line.

A chord is really an illusion: the momentary, vertical result of four independent melodies sounding at once. Controlling those four lines is called voice leading, and the classic laboratory for learning it is four-part choral writing: SATB (soprano, alto, tenor, bass).

Click any example to hear it. Examples with mistakes show the problem notes in red.

Writing Four Parts on the Grand Staff

In this course, four-part writing goes on a grand staff with two voices on each staff:

• Treble staff: soprano (stems up) and alto (stems down).
• Bass staff: tenor (stems up) and bass (stems down).
• Stem direction shows which voice is which, so keep it consistent even when a note is high or low on the staff.
• If two voices on one staff sing the same note, write one notehead with two stems.

Keep every voice within the ranges from Chapter 1 (soprano C4–G5, alto G3–D5, tenor C3–G4, bass E2–C4), and mostly in the middle of each range.

Spacing: Managing the Acoustic Load

Low frequencies take up more acoustic space than high ones. Notes crowded together low on a piano sound muddy, while the same intervals high up sound clear. Four-part writing reflects this with two spacing rules:

• No more than an octave between soprano and alto, or between alto and tenor.
• The bass may be any distance below the tenor, even more than an octave.

Within these rules, the upper three voices can be arranged in two ways:

1. Close position: soprano, alto, and tenor are as close together as possible, spanning less than an octave. No chord tone could fit between them.
2. Open position: the upper voices span an octave or more, with room for chord tones between them, creating a fuller, more spacious sound.

Doubling: The Mathematics of Four Parts

A triad has three notes, but we have four voices, so one chord member must be doubled (sung by two voices). Which one you double affects how stable the chord sounds and how smoothly the voices can move next. These are the standard guidelines:

Why never double the leading tone? It has an overwhelming urge to rise to the tonic. If two voices both have it, either both rise (creating parallel octaves, Chapter 8) or one must ignore its tendency. The same logic applies to a chordal seventh, which must fall.

Sometimes a chord is incomplete. You may leave out the fifth of a triad (tripling the root), especially in the final tonic chord, but never leave out the third, which identifies the chord as major or minor.

Crossing and Overlap

Each voice should stay in its own lane. Voice crossing happens when a lower voice goes above a higher one (the alto above the soprano, for example). Voice overlap happens between two chords, when a voice moves past where its neighbor just was. Both blur the independence of the lines, and in strict four-part writing we avoid them.

The Singable Line

Treat the alto and tenor with as much respect as the soprano melody. A good line moves mostly by step, uses small leaps, avoids awkward augmented intervals, and holds common tones when a note belongs to both chords. If a part is hard to sing, it's probably poor voice leading. You'll learn the specific rules for connecting chords in Chapter 8.

Try It: Voice-Leading Checker

Type your own four-part chords, and the checker will flag range, spacing, crossing, doubling, and (looking ahead to Chapter 8) parallel fifths and octaves. Start by fixing the errors in the example below.

Check Your Understanding