Authentic and Plagal Cadences in Music
Frank Herrlinger
Co-Founder of the Music Interval Theory Academy & Interval Theory Composer
Disclaimer: This article has been adapted from content originally published on my website. For the full version, including audio examples and more in-depth insights, please visit:
Cadences play a fundamental role in Western music, shaping harmonic flow and resolution. They follow a stepwise motion through the Circle of Fifths, a powerful tool for structuring chord progressions.
By following this natural movement—without skipping steps—you can craft harmonically rich and cohesive progressions that resonate with listeners. Whether composing for film, orchestration, or songwriting, mastering these cadential motions can elevate your musical storytelling.
Authentic Cadences
Before diving into practical examples, let’s break down how tones move within the Circle of Fifths when following the authentic direction.
In this motion, we progress counterclockwise, with each step moving five chromatic steps up—a pattern known as Root Cycle 5 (RC5). This consistent interval creates a natural harmonic flow, reinforcing a sense of resolution.
By stacking notes in this ascending manner, composers establish strong, predictable progressions that serve as the backbone of many musical styles. Mastering this movement is key to creating harmonic clarity and depth in your compositions.
When mapping Root Cycle 5 (RC5) in the bass clef, you'll notice an interesting pattern:
This adjustment is intentional—it keeps all tones within a single octave, ensuring a smooth and practical foundation for composition.
But here’s the key takeaway: instead of focusing solely on physical movement, shift your attention to the Harmonic Weight—the shortest distance between two bass notes. Within the Circle of Fifths, this distance is consistently five chromatic steps, either ascending or descending.
Understanding Harmonic Weight is crucial for mastering voice leading and creating seamless, professional-sounding progressions.
In authentic cadences, the harmonic weight always moves five chromatic steps up—and this is where the magic happens!
It’s important to distinguish harmonic weight from physical movement. While physical movement may vary based on notation choices, harmonic weight remains consistent and plays a crucial role in shaping strong, well-structured progressions.
By focusing on harmonic weight rather than just interval placement, you gain greater control over voice leading and harmonic flow, leading to smoother and more intentional compositions.
Theory can feel abstract without hearing it in action, so let’s add some major triads on top of our root tones to create a harmonic structure.
In Interval Theory, we don’t adhere to a fixed key. Instead, each root tone establishes its own temporary tonal center. This approach differs from the traditional Diatonic system, but it unlocks an entirely new set of creative possibilities.
By embracing this flexible harmonic framework, composers gain more freedom to explore unconventional progressions, break away from predictable patterns, and craft truly original music.
Our harmonic framework is already shaping up beautifully—but this is just the beginning! By alternating major and minor triads, we introduce even more variety and depth, opening up new creative possibilities for composition.
What’s exciting about this approach is that it’s 100% technique-driven—you don’t need to rely solely on inspiration to make it work. Yet, as we continue, we’ll naturally weave in creative choices that elevate the music even further.
These structured decisions are part of the core techniques we teach inside the Academy, helping composers streamline their workflow while maintaining musical freedom.
One of the great things about this approach is its flexibility—you can switch between major and minor triads at any time, tailoring the progression to fit your creative vision.
For now, we’ve followed a simple pattern, but this is just a starting point. Use it as inspiration to develop your own harmonic ideas. Take some time to listen, experiment, and explore—each variation offers new possibilities that can shape the mood and direction of your composition.
By giving yourself options and harmonic colors early in the process, you’ll save valuable time when transitioning to sketching and orchestration, allowing you to compose with greater efficiency and clarity.
Plagal Cadences
Now, let’s shift our focus to plagal cadences. The key difference between authentic and plagal cadences lies in the direction of harmonic weight in the bass register.
This simple change in direction has a profound impact on harmonic resolution, offering a softer, more reflective sense of closure.
Here’s a fascinating insight that might be new to you—authentic and plagal cadences are reflections of one another.
Why does this matter? Because it serves as a gateway into Negative Harmony, unlocking an entirely new palette of sounds and harmonic possibilities.
Everything we’ve explored on the authentic side applies just as effectively to plagal cadences—only with the harmonic weight moving in the opposite direction. This mirrored relationship expands the ways we can craft progressions, providing fresh tools for composers seeking innovative harmonic motion.
By recognizing this connection, you gain greater flexibility in shaping musical phrases, whether you want a strong resolution or a softer, more open-ended cadence.
At first glance, understanding harmonic weight between neighboring root tones might not seem like a game-changer—but trust me, it is! This knowledge becomes invaluable when applying more advanced techniques like extended roots, complex chord structures, or substitute voice-leading.
Here’s the key takeaway:
Since these two movements are mirrors of one another, mastering both allows you to navigate harmonic motion with greater control and intention.
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One of the biggest advantages of not writing in a fixed key is the freedom to switch between major and minor triads at any point in your cadence. This flexibility allows for greater expression and harmonic variety.
However, while experimenting with triads, pay close attention to the movement in the lower register—ensure it follows a stepwise motion of five chromatic steps up (authentic) or down (plagal). This simple yet effective approach ensures that your progressions sound harmonically solid and naturally musical.
I’m a big fan of triads because they connect to so many fascinating harmonic concepts—Polytonality, Negative Harmony, Equivalents, Pentatonics, and more. They are versatile, easy to work with, and sound fantastic in a variety of contexts.
Here’s an example of plagal cadences using alternating major and minor triads on top.
Enhancing Harmonic Depth with Substitute Tones
Want to bring more color and variation to your harmonies? A simple yet powerful approach is using substitute tones. But here’s the key: start simple with basic triads before introducing substitutions. This ensures clarity and structure in your composition. Remember—build from simple to complex, not the other way around!
Here are some effective scale-tone substitutions for triads that can add richness and depth to your progressions:
These substitutions also work beautifully as passing tones, introducing smooth movement and enhancing voice-leading.
In a practical example, I apply these substitutions to authentic cadences (RC5 ascending), alternating major and minor triads while incorporating line movement. If you analyze the bass and melody, you’ll still find the foundation of the original authentic cadence—only now, with a more dynamic and expressive flow.
Streamlining Your Composition Process: A Step-by-Step Approach
Selecting the right substitutions can take time, but here’s the secret to speeding up your workflow: follow a structured order of steps. This ensures clarity, efficiency, and better musical results.
1?? Start simple – Write out your root tones first.
2?? Add harmonic structure – Layer major and minor triads above.
3?? Introduce substitutions – Apply alternate scale tones to enrich the harmony.
?? Pro Tip: Keep line movement as a separate step—don’t mix it in too early. This keeps your writing process clear and avoids unnecessary complexity.
Now comes the exciting part! We take this structured sketch and expand it into a full orchestral piece.
Orchestrating the Sketch
Many composers hit a roadblock at this stage. They develop a solid sketch using composition techniques but struggle to move forward into orchestration. Sound familiar?
Here’s the key to overcoming this challenge: composition and orchestration are not separate processes—they are deeply connected.
When you compose, you’re already making crucial orchestration decisions:
? Choosing registers – This dictates which instruments will best carry the theme.
? Shaping phrasing – This influences dynamics, articulation, and expressive choices.
? Building sections – Small groups of 2-4 parts naturally guide instrumentation choices.
By recognizing that your compositional choices inform your orchestration, the process becomes far less intimidating—it’s just an extension of what you’ve already written!
At the Music Interval Theory Academy, I teach some core concepts about orchestration, including:
? Completing your instrument sections – Ensuring a balanced, full sound.
? Thinking in functions – Assigning clear musical roles to each instrument.
? Creating contrast – Enhancing clarity and dynamic variation.
? Knowing the "cash registers" – Utilizing optimal ranges for each instrument.
? Following the Harmonic Series (Overtone Series) – Building resonance and natural tonal blending.
? Telling a story with your music – Making every note serve the narrative.
Orchestration is Like Solving a Puzzle ??
There’s no single "correct" orchestration—many solutions can work, but starting with the right approach makes a huge difference. Instead of aimlessly experimenting, commit to your first puzzle piece and build around it.
The secret to success? Having a clear, structured plan rather than spending hours searching for ideas. With the right mindset and strategy, you’ll develop orchestrations that sound cohesive, expressive, and professional—faster and with greater confidence!
Conclusion & Summary
Authentic and plagal cadences might seem like familiar clichés, but they remain some of the most powerful harmonic tools in composition. Since nearly every composer relies on the Circle of Fifths (and for good reason), the challenge is finding ways to set yourself apart creatively.
Following the step-by-step motion of the Circle of Fifths provides a strong harmonic foundation. From there, you can elevate your writing by applying advanced composition techniques like Interval Theory, while infusing your own musical identity into the process.
Key Takeaways from Our Exploration:
? Authentic and plagal cadences form some of the strongest chord progressions in music.
? They are mirror images of each other—authentic moves up (RC5 ascending), while plagal moves down (RC5 descending).
? Start simple when writing out chords over your bass notes, then gradually add complexity.
?? Pro Tip: Train your ears to recognize the 5-interval in the bass—it’s everywhere in music! Once you start listening for it, you’ll be amazed at how frequently authentic and plagal cadences shape harmonic movement.
Disclaimer: This article has been adapted from content originally published on my website. For the full version, including audio examples and more in-depth insights, please visit: