The Phrygian scale is another one of the seven musical modes and is characterized by its dark and somewhat exotic sound. It is often used in music to evoke tension, mystery, or a sense of the ancient or the Eastern world.

Construction:

The Phrygian scale is built using the following interval pattern:

• Half step

• Whole step

• Whole step

• Whole step

• Half step

• Whole step

• Whole step

In E Phrygian, it would be:

• E (root)

• F (half step)

• G (whole step)

• A (whole step)

• B (whole step)

• C (half step)

• D (whole step)

• E (octave)

Features:

• Minor tonality: Like the Dorian mode, the Phrygian mode has a minor tonality, characterized by a minor third (between the root and the third degree).

• Flat second degree: The defining feature of the Phrygian mode is its flat second degree (compared to the natural minor scale), which gives it a distinctly Spanish or Middle Eastern flavor.

Chord Construction:

• Tonic chord (i): E minor (E, G, B)

• Supertonic chord (II): F major (F, A, C)

• Mediant chord (III): G major (G, B, D)

• Subdominant chord (iv): A minor (A, C, E)

• Dominant chord (v): B diminished (B, D, F)

• Submediant chord (VI): C major (C, E, G)

• Subtonic chord (VII): D minor (D, F, A)

Usage:

• Flamenco and Spanish music: The Phrygian mode is heavily used in flamenco and Spanish music, often associated with the "Andalusian cadence."

• Classical and Contemporary: It’s used in classical music to evoke ancient or mystical atmospheres and in contemporary genres like metal and jazz to create tension and exoticism.

• Film Scores: The scale is often used in film scores to suggest danger, mystery, or ancient settings.

The Phrygian scale is powerful in setting a particular mood, especially when a composer or musician wants to evoke an intense, dark, or exotic atmosphere.