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Understanding musical cadences is essential for analyzing and appreciating classical compositions. One such cadence, the plagal cadence, often appears at the end of movements to create a sense of resolution. This article provides a clear, step-by-step guide to help students and teachers identify a plagal cadence within a sonata movement.
What is a Plagal Cadence?
A plagal cadence, sometimes called the Amen cadence, occurs when the harmony moves from the subdominant (IV) chord to the tonic (I) chord. It is characterized by the progression IV – I. Unlike the perfect authentic cadence (V – I), the plagal cadence provides a softer, more subdued resolution.
Step 1: Listen for the Ending
Start by listening carefully to the end of the sonata movement. Pay attention to the final chords and how they sound. A plagal cadence often occurs near the conclusion, giving a sense of closure that is less forceful than a perfect authentic cadence.
Tip:
- Use headphones for clearer sound.
- Listen multiple times if needed.
Step 2: Identify the Chords
Once you focus on the ending, try to identify the last two chords. The key signature and the notes played will help determine the chords. The plagal cadence involves a move from the IV chord to the I chord.
How to recognize the IV and I chords:
- The IV chord typically contains the notes F, A, C in the key of C major.
- The I chord contains the notes C, E, G.
Step 3: Confirm the Progression
Play or analyze the chords to confirm the progression. If the last two chords are IV followed by I, and they resolve smoothly, you are likely observing a plagal cadence.
Additional Tips for Identification
Some cadences may be less obvious if the harmony is complex or if the composer uses embellishments. In such cases, look for:
- Harmonic analysis of the passage.
- The bass line movement from the IV to I chord.
- Context within the movement — is it at the end?
Summary
To identify a plagal cadence in a sonata movement, listen for the characteristic IV – I progression near the conclusion. Confirm the chords through harmonic analysis, and consider the overall musical context. With practice, recognizing this cadence will become an intuitive part of your musical analysis skills.