The Lydian dominant scale is a musical mode often used in jazz and fusion genres. It’s essentially a Lydian scale with a flattened seventh degree. To understand it better, think of it as the fourth mode of the melodic minor scale. For example, if you play the melodic minor scale starting on its fourth note, you get the Lydian dominant mode.

In terms of intervals, the Lydian dominant scale consists of:

• Root
• Major second
• Major third
• Augmented fourth (#4)
• Perfect fifth
• Major sixth
• Minor seventh (b7)

This combination gives the scale a bright and somewhat “dreamy” quality from the #4 (augmented fourth), paired with a bluesy or dominant feel from the flat seventh.

The Lydian dominant scale is commonly used over dominant 7 chords with altered or sharpened extensions, especially the #11 (the augmented fourth). It’s perfect for improvising over dominant chords that resolve to a tonic, adding color and tension without sounding too dissonant. Jazz musicians often use it for V7 chords in minor keys, or anytime they want a dominant sound that feels modern and smooth.

In summary, the Lydian dominant scale adds an interesting twist to dominant chords by combining the bright #4 with the classic dominant b7, making it a valuable tool for creating sophisticated and vibrant harmonies in jazz and beyond.