If you’re a music enthusiast or a student of music theory, you may have come across the term “IAC.” But what does it mean? In this article, we’ll explore the concept of IAC in music theory and its significance.

What Is IAC?

IAC, or “imperfect authentic cadence,” is a type of cadence that is commonly found in Western classical music and other genres. A cadence is a musical phrase that brings a sense of closure or resolution to a piece of music. It’s like the period at the end of a sentence – it tells us that the musical idea has come to an end.

There are different types of cadences, including perfect authentic cadences (PAC), plagal cadences, and deceptive cadences. IAC is one type of imperfect cadence.

What Does IAC Sound Like?

An IAC typically sounds like a V chord moving to a chord other than I (the tonic). In other words, it’s a progression from the dominant to another chord that doesn’t sound as final as the tonic. For example, a common IAC progression is V – vi (the submediant).

An IAC may also involve some sort of embellishment or extension before reaching the final chord. It’s called “imperfect” because it doesn’t bring as much closure as a PAC.

Why Is IAC Important?

IAC serves an important function in music by adding variety and interest. It creates tension and expectation, making listeners want to hear more. Without these variations in cadences, music can become predictable and boring.

In addition to its role in creating tension and interest, IAC can also be used for expressive purposes. For example, composers might choose an IAC over a PAC to create a sense of longing or yearning.

Examples of IAC in Music

IAC can be found in a wide range of musical genres. Here are a few examples:


In summary, IAC is a type of cadence that adds interest and variety to music. It doesn’t provide as much closure as a PAC, but it creates tension and expectation that keeps listeners engaged. Whether you’re a composer, performer, or simply a listener, understanding IAC can help you appreciate and analyze music on a deeper level.