#AP Music Theory: The Night Before Cram Session 🎶

Hey there, future music maestro! Feeling the pressure? Don't worry, we've got this. Let's turn those notes into a symphony of understanding. This guide is designed to be your go-to resource for a confident test day. Let's dive in!

#4.1: Harmony and Voice Leading I

#What is Voice Leading?

Voice leading is how individual voices move from chord to chord. Think of it as the choreography of your musical lines. It’s all about creating smooth, pleasing transitions. We're focusing on the Common Practice Period (CPP), roughly 1650-1900, where these rules were developed.

#Types of Motion

In four-part writing, voices move in four ways:

1. Parallel Motion: Voices move in the same direction by the same interval.
2. Similar Motion: Voices move in the same direction but by different intervals.
3. Oblique Motion: One voice stays put while the other moves.
4. Contrary Motion: Voices move in opposite directions.

#18th-Century Voice Leading Rules

These are the golden rules for smooth voice leading:

• Stepwise Motion: Voices should move mostly by step, avoiding big leaps.
• Common Tones: Keep common tones in the same voice when moving between chords.
• SATB Order: Maintain Soprano-Alto-Tenor-Bass order to avoid voice crossing.
• Avoid Parallel Fifths and Octaves: Don't move to a perfect fifth or octave from another perfect fifth or octave in parallel motion. This also applies to contrary motion and nonadjacent chords.

* **Melodic Intervals**: Use major and minor seconds, thirds, perfect fourths, and perfect fifths melodically. Avoid augmented, diminished intervals, and leaps larger than a perfect fifth. * **Leading Tone**: Resolve the leading tone in an outer voice (soprano or bass) up by step. * **Implied Chords**: Ensure soprano notes make harmonic sense with implied chords. * **Acceptable Progressions**: Use tonic, supertonic, subdominant, and dominant triads following harmonic progression norms. * **Repeated Harmonies**: Okay on strong beats, or weak beats at the beginning of a phrase. * **Bass Line**: Balance upward and downward motion with steps and leaps. Leaps are more common in the bass than in upper voices. * **Bass Leaps**: Use thirds, perfect fourths, fifths, sixths, and octaves. Octave leaps should change direction. Successive leaps can outline a triad. * **Repeated Bass Notes**: Okay on strong b...