Lydian Dominant Scale

The Lydian dominant scale is Mixolydian with a raised fourth — a dominant seventh scale with a tritone substitution built in. It has the bright, suspended quality of Lydian combined with the flat seventh of a dominant chord. It's the sound of tritone substitution, of the IV7 chord in a blues, of Bill Evans's modal harmony, and of bossa nova chord voicings.

Construction

The 4th mode of the melodic minor scale.
C Lydian Dominant (4th mode of G melodic minor):
C D E F# G A B♭ C

Formula: 1  2  3  #4  5  6  ♭7
Compared to C Mixolydian: raises the 4th (F → F#)
Compared to C Lydian: lowers the 7th (B → B♭)

Parent Scale

G melodic minor: G A B♭ C D E F# G
4th mode (start on C): C D E F# G A B♭ C
= C Lydian Dominant

Any Lydian dominant scale is the 4th mode of the melodic minor scale rooted a fifth below it: C Lydian Dominant = G melodic minor. F Lydian Dominant = C melodic minor. B♭ Lydian Dominant = F melodic minor.

Sound and Character

Bright, forward-leaning, sophisticated. The ♯4 against a dominant seventh chord creates a particular harmonic colour — the tritone (♯4) is the same interval as the tritone in the dominant seventh chord itself (between the 3rd and ♭7), so Lydian Dominant reinforces the chord's harmonic tension in a uniquely rich way.

The most common use is over the tritone substitution dominant. If the original chord is G7 (going to C), the tritone sub is D♭7 (also going to C — they share the same tritone). D♭ Lydian Dominant over a D♭7 chord heading to C is a characteristic modern jazz move.

Uses

• Tritone substitution dominants — the natural scale choice for a ♭II7 chord.
• IV7 chord in blues — D7 in an A blues (the IV7). Lydian dominant on D gives you a richer, jazzier sound than straight Mixolydian.
• Static dominant chords — over any dominant 7th chord that doesn't resolve to a tonic a fifth below, Lydian dominant often sounds better than Mixolydian because the ♯4 avoids the "expected" sound.
• Modal jazz — "Maiden Voyage" by Herbie Hancock is built largely on Lydian dominant harmony. The suspended, open sound comes directly from this scale.

Comparison: Altered vs. Lydian Dominant

Over G7 → Cmaj7:
G Altered:          G A♭ B♭ B D♭ E♭ F  (maximum tension, resolution-driven)
G Lydian Dominant:  G A B C# D E F     (bright tension, can be static)

Altered is for strong ii-V-I resolutions — the tension demands release.
Lydian Dominant is for floating dominant sounds that don't urgently resolve.