The Evolution of the Supertonic: A Journey Through Music History

📚 What is the Supertonic?

The supertonic is the second degree of a diatonic scale. In simpler terms, it's the note that's one whole step above the tonic (the 'home' note of a key). The term 'supertonic' comes from Latin, meaning 'above the tonic'. It plays a crucial role in creating harmonic movement and tension within a musical piece.

📜 A Brief History of the Supertonic

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• Early Music: The supertonic's function can be traced back to early Western music, including Gregorian chants and medieval polyphony. While not always explicitly recognized as a distinct harmonic element, the stepwise motion from the supertonic to the tonic was a common melodic feature.
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• Baroque Era: During the Baroque period (1600-1750), composers like Bach and Handel began to more consciously utilize the supertonic chord (ii or ii°) as a means of creating harmonic tension and resolution, especially in cadences.
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• Classical Period: The Classical era (1750-1820), with composers like Mozart and Beethoven, saw the standardization of harmonic practices. The supertonic chord became an integral part of the dominant-tonic (V-I) cadence, often appearing as a pre-dominant harmony.
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• Romantic Era: In the Romantic era (1820-1900), composers such as Chopin and Brahms explored more chromaticism and harmonic complexity. The supertonic chord was frequently altered or used in inversions to create richer and more expressive harmonic textures.
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• 20th Century and Beyond: The 20th and 21st centuries have witnessed a further expansion of harmonic language, with composers experimenting with atonality, polytonality, and microtonality. While the traditional function of the supertonic may be less strictly adhered to, its influence can still be detected in various contemporary musical styles.

🔑 Key Principles of the Supertonic

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• Scale Degree: The supertonic is the second degree of the scale. For example, in the key of C major, the supertonic is D.
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• Chord Function: The supertonic typically functions as a pre-dominant chord, leading to the dominant (V) chord.
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• Roman Numeral Analysis: In Roman numeral analysis, the supertonic chord is represented as ii (minor) in major keys and ii° (diminished) in minor keys.
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• Harmonic Movement: The supertonic chord creates a sense of instability and anticipation, which is resolved by the dominant and tonic chords.
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• Inversions: The supertonic chord can be used in different inversions to create different bass lines and voice leading.

🎶 Real-World Examples

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• "Canon in D" by Johann Pachelbel: The supertonic chord is used extensively to create the harmonic progression that characterizes this piece.
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• "Für Elise" by Ludwig van Beethoven: The supertonic appears in the famous opening bars, contributing to the piece's harmonic structure.
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• Many Blues Progressions: The supertonic can be found as part of more complex turnarounds and chord substitutions.

📈 Mathematical Representation of the Supertonic

In music theory, intervals can be represented mathematically. The interval between the tonic and the supertonic is a major second, which corresponds to a frequency ratio of approximately $9:8$. This ratio can be derived from the circle of fifths and equal temperament calculations.

For example, if the frequency of the tonic (I) is $f$, then the frequency of the supertonic (II) can be approximated as:

$f_{II} \approx f * \frac{9}{8}$

🧪 Supertonic in Scientific Context

The perception of the supertonic and its role in creating tension and resolution is also a subject of psychoacoustic study. Research shows that our brains are wired to recognize and respond to specific harmonic relationships, like the movement from the supertonic to the dominant, and finally to the tonic. These relationships are deeply ingrained in our cognitive processing of music.

✅ Conclusion

The supertonic is a fundamental element of music theory, playing a vital role in creating harmonic movement and tension. From its early origins in medieval music to its sophisticated use in contemporary compositions, the supertonic continues to be an essential tool for composers and musicians. Understanding the supertonic enriches our appreciation of music and provides valuable insights into the structure and function of musical compositions.