Hello! As a music theory expert, I'm here to help you understand the intricacies of musical cadences. Cadences are the musical punctuation that signal the end of a musical phrase or piece. They are a crucial part of the structure and expression of music, and they come in various types, each with its own unique characteristics and effects.
The IV to I cadence is a harmonic progression that you might be referring to. The Roman numerals IV and I represent the fourth and first scale degrees, respectively, in a diatonic scale. This progression is known as the "plagal cadence" when it moves from the subdominant (IV) to the tonic (I). Plagal cadences are often associated with a more subdued or peaceful resolution compared to the more definitive and strong resolution of the perfect authentic cadence (V to I).
Now, let's delve into the details of the IV to I cadence and its various interpretations:

1. Plagal Cadence: The most straightforward interpretation of the IV to I progression is as a plagal cadence. This is a type of authentic cadence, which means it provides a sense of resolution or finality. However, it is considered "plagal" because it starts on the fourth scale degree instead of the fifth, which is more common in the perfect authentic cadence (V to I).

2. Minor Plagal Cadence: When the IV chord is minor, the progression is sometimes referred to as a "minor plagal cadence." This gives the cadence a slightly different emotional quality compared to the major version. The minor chord can introduce a touch of melancholy or introspection before resolving to the major I chord.

3. Combined Cadence: As you mentioned, sometimes a combination of major and minor plagal cadences is used, which is notated as IV-Civ-CI. This progression starts with a major IV chord, moves to a minor iv chord (lowercase 'iv' indicates a minor chord), and then resolves to the major I chord. This combination can create a more complex emotional journey within the cadence, starting with a more stable and bright major chord, moving through a more introspective minor chord, and finally resolving to the major tonic.
It's important to note that the interpretation of a cadence can be influenced by the context in which it is used. Factors such as the key of the piece, the surrounding chords, and the overall style and mood of the music can all affect how a listener perceives the cadence.
In summary, the IV to I cadence is a versatile and expressive tool in a composer's arsenal. Whether used as a straightforward plagal cadence, a minor plagal cadence, or a combination of both, it can provide a rich and satisfying sense of resolution to a musical phrase.
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It may be noticed that the plagal cadence, "leaves open the possibility of interpretation as V-CI-CV" rather than I-CIV-CI. The term "minor plagal cadence" is used to refer to the iv-CI progression. Sometimes a combination of major and minor plagal cadence is used (IV-Civ-CI).read more >>