Mastering 6/4 Chords: Your Ultimate AP Music Theory Guide 🎶

Hey there! Let's dive into the world of 6/4 chords. They can seem tricky, but with a clear understanding, you'll be acing those AP Music Theory questions in no time. Remember, 6/4 chords are generally weak and used as embellishments, not as structural harmonies. Let's break it down!

Understanding 6/4 Chords: An Overview

Weak Chords: 6/4 chords generally sound weak and are used as embellishments rather than structural harmonies.
Embellishments: They often decorate or connect stronger harmonies.

Key Concept

Cadential 6/4: The I 6/4 before a V at a cadence, acting as a dominant embellishment. It's a tonic chord by name but a dominant chord by function.

-   Bass is on the dominant scale degree.
-   Upper voices resolve to the dominant chord.

Other 6/4 Types: Besides cadential, we have neighboring, passing, and arpeggiated 6/4 chords. Let's explore each!

Neighboring (Pedal) 6/4 Chords

Definition: Also known as pedal 6/4 chords, these occur when the 3rd and 5th of a root-position triad are embellished by upper neighbor tones while the bass stays the same.
How it works: The bass note remains constant, while the upper voices move to neighboring tones and then back.
Example: In Ab Major, embellishing a I chord with a IV 6/4. The bass stays on Ab, while the upper voices move from C and Eb (I chord) to Db and F (IV 6/4), then back to C and Eb.

Caption: Example of a pedal 6/4 chord in C Major. The bass stays on C, while the upper voices move to neighboring tones and then back.

Passing 6/4 Chords

Passing Tone: A note that connects two other notes stepwise, creating a sense of movement. It's a type of non-chord tone. Think of it as a bridge between two stable points.
Harmonizing Non-Chord Tones: You can harmonize a passing tone without adding harmonic value. It's about melodic interest, not harmonic progression.
Example: A I-V 6/4-I6 progression. The bass line moves stepwise (tonic-supertonic-mediant), with the V 6/4 acting as a passing chord.

Caption: Example of a passing 6/4 chord in Eb Major. The bass line moves stepwise (Eb-F-G), creating a smooth transition.

Voice Leading with Passing 6/4 Chords

Weak Beat: The 6/4 chord should almost always be on a weak beat.
Stepwise Motion: Upper voices should move stepwise into and out of the passing 6/4 chord. This often creates a nice voice exchange between the soprano and bass lines.

Memory Aid

Passing 6/4 Rule: Weak beat, stepwise feet! Remember that the 6/4 chord is on a weak beat and the voices move in steps.

Arpeggiated 6/4 Chords

Arpeggio: A broken chord where notes are played in sequence. Think of it as a chord being 'strummed' rather than played all at once.
Arpeggiated 6/4: 6/4 chords used to harmonize arpeggios in the bass line.
Example: A I-I6-I 6/4 progression. The bass line arpeggiates (tonic-mediant-dominant), while the upper voices often sustain.

Caption: Example of an arpeggiated 6/4 chord. The bass line arpeggiates (C-E-G), while the upper voices sustain.
Common Usage: Often seen in waltzes with a I chord on the downbeat and I 6/4 chords on the upbeats.
Typical Chords: Usually I or V 6/4 chords are used in arpeggiated patterns.

Other Voice Leading Rules

Unacceptable Progressions: Avoid these progressions as they move backwards in the T-PD-D-T phrase:
- V-IV
- V-ii
- ii-iii
- IV-iii
- ii-I
- V-vi6
- iii-viio
Chords to Avoid:
- Root position viio chords
- vi6 chords
- iii6 chords

Common Mistake

These chords are rare and usually indicate an error. Double-check your work if you see them.

Final Exam Focus

Prioritize: Focus on cadential, passing, and arpeggiated 6/4 chords. Understand their function and voice leading.
Common Questions: Expect questions that ask you to identify or write different types of 6/4 chords in a given context.

Exam Tip

Time Management: Quickly identify the bass line and the function of the 6/4 chord. Look for stepwise motion and weak beats.

Pitfalls: Avoid using 6/4 chords as structural harmonies. Always ensure they are used as embellishments.
Strategy: Practice writing out different 6/4 chord progressions. Pay attention to voice leading and weak/strong beats.

Practice Question

Multiple Choice Questions

In a musical passage, a I 6/4 chord is followed by a V chord at a cadence. This is an example of a: a) Passing 6/4 chord b) Arpeggiated 6/4 chord c) Cadential 6/4 chord d) Neighboring 6/4 chord
A V 6/4 chord is used to connect a I chord and a I6 chord. The bass line moves stepwise. This is an example of a: a) Cadential 6/4 chord b) Passing 6/4 chord c) Arpeggiated 6/4 chord d) Neighboring 6/4 chord

Free Response Question

Instructions: Analyze the following four-part harmony excerpt in C Major. Identify the type of 6/4 chord used and explain its function.

[Music Excerpt in C Major]
C - G/B - C/G - G
I  -  V6/4 - I6/4 - V

Scoring Breakdown:

(1 point) Correctly identify the 6/4 chord as a passing 6/4 chord.
(1 point) Explain that the V 6/4 is a passing chord between I and I6. - (1 point) Explain that the bass line moves stepwise.
(1 point) Explain that the 6/4 chord occurs on a weak beat.

Short Answer Question

Explain the difference between a neighboring 6/4 chord and a passing 6/4 chord. Provide an example of each in a musical context.

Answer:

A neighboring 6/4 chord occurs when the upper voices move to neighbor tones while the bass stays the same. For example, I - IV6/4 - I. The bass remains the same, while the upper voices move up and back.
A passing 6/4 chord occurs when the bass line moves stepwise, and the 6/4 chord is used as a passing tone between two other chords. For example I - V6/4 - I6. The bass line moves stepwise from tonic to supertonic to mediant.

Alright, you've got this! Keep practicing, and you'll be a 6/4 chord master in no time. Good luck on your exam! 🚀

Additional 6/4 chords

Samuel Baker