Fadd9 guitar chord — root mapping, fingerings, arpeggios, triads, pentatonic, scales

Lydian is a major mode with a raised 4th. The #4 removes the usual half step between III and IV and supports a maj7#11 tonic without clashing with the major 3rd. Its characteristic harmonic move is I – II, with major chords on both degrees. Lydian is common in film music, modal jazz, fusion and progressive rock when a major sound is needed without the usual subdominant weight.

Lydian is a major mode with a raised 4th degree. It differs from Ionian, or the ordinary major scale, by one note: it uses the augmented 4th #4 instead of the perfect 4th 4. The major 3rd preserves its major quality, while #4 provides the defining modal color and forms a tritone with the tonic. The raised 4th also produces a major II chord instead of the minor ii found in Ionian. Within the common spectrum of modal brightness, Lydian is considered the brightest of the seven diatonic modes. Its defining degree is #4, or #11 relative to the tonic chord.

1 — tonic: the modal center and the root of the major I and Imaj7 chords.

2 — major 2nd / 9th: the root of the major II chord; over the tonic chord it functions as a 9.

3 — major 3rd: establishes the mode’s major quality, belongs to I and Imaj7, and serves as the root of the minor iii chord.

#4 — augmented 4th / sharp 11th: the defining degree of the mode. It distinguishes Lydian from Ionian, forms the 3rd of the major II chord, and serves as the root of the diminished #iv° chord.

5 — perfect 5th: a stable tone of the tonic major chord and the root of the major V chord. Degree #4 lies a semitone below it and may tend upward toward 5.

6 — major 6th / 13th: functions as a 13 over the tonic chord and serves as the root of the minor vi chord.

7 — major 7th / leading tone: belongs to Imaj7, lies a semitone below the tonic, and tends to resolve upward to 1. The chord built on the 7th degree is minor vii rather than the diminished vii° found in ordinary major.

Harmonizing the scale in triads produces:

I—major; II — major; iii — minor; #iv° — diminished; V — major; vi — minor; vii — minor.

The diatonic seventh chords are Imaj7, II7, iii7, #ivø7, Vmaj7, vi7, and vii7.

The mode’s principal harmonic marker is the major II chord over a major tonic. The 3rd of II is the defining degree #4. Alternating I–II or Imaj7–II7 exposes the Lydian color without introducing the natural 4th.

The II chord has the structure of a dominant seventh chord, but in a modal context it does not have to resolve to V. When II7 consistently resolves to V, it may be heard as the secondary dominant V/V rather than as an independent Lydian harmony.

In C Lydian, the triads are C D Em F#dim G Am Bm; the seventh chords are Cmaj7 D7 Em7 F#m7b5 Gmaj7 Am7 Bm7.

Lydian is used over major and major seventh chords when the harmony supports a raised 4th degree. In jazz chord-scale theory, it is the primary choice for a maj7#11 chord because the degrees 1 3 5 7 #11 match the chord tones and its defining extension. For example, C Lydian is used over Cmaj7#11.

Both Ionian and Lydian may be used over an ordinary maj7 chord; the correct choice depends on the key, melody, and surrounding harmony. When the music explicitly contains a natural 4, the Lydian #4 will conflict with it.

Within a major key, Lydian naturally corresponds to the IVmaj7 chord. For example, F Lydian is used over Fmaj7 in the key of C major and contains the same notes as C major. In independent modal music, the mode is often established through a tonic pedal, a sustained Imaj7#11 chord, or alternating I–II harmony.

Lydian is the fourth mode of the major scale. Its relative parent major scale begins a perfect 5th above the Lydian tonic. For example, C Lydian and G major contain the same notes, C D E F# G A B, but C is the center in C Lydian rather than G.

Its closest parallel mode is Ionian, 1 2 3 4 5 6 7. It differs only in the 4th degree: Lydian uses #4. Lydian Dominant has the formula 1 2 3 #4 5 6 b7 and differs through its lowered 7th. Lydian Augmented has the formula 1 2 3 #4 #5 6 7 and differs through its raised 5th. Lydian #2 has the formula 1 #2 3 #4 5 6 7 and is the sixth mode of harmonic minor.

Over maj7 or maj7#11, begin with the chord tones 1 3 5 7. To make the line sound specifically Lydian, emphasize #4: use it as the #11, sustain it over the tonic chord, and include it in motions such as 3–#4–5, 5–#4–3, 2–3–#4, and #4–5. Without #4, the melody can easily sound like ordinary major.

Unlike the natural 4 in Ionian, degree #4 does not form a minor 2nd against the chord’s major 3rd. It can therefore function as a sustained upper extension over maj7#11 when the harmony supports it, although it still forms a tritone with the tonic and retains noticeable tension.

Over alternating I–II harmony, follow the notes of each chord. Degree #4, which functions as the #11 over I, becomes the major 3rd of II. In C Lydian, for example, F# is the #11 over Cmaj7 and the 3rd of D or D7.

To preserve the Lydian center, return regularly to 1, end phrases on it, and support it with a tonic bass or pedal point. If the motion #4–5, the V chord, or resolutions toward the relative major tonic are emphasized too strongly, 5 may begin to sound like the new tonal center.

Lydian is a major mode with a raised 4th degree. Its foundation is a major tonic, I or Imaj7, while its defining sound is #4, which functions as a #11 and produces a major II chord. Unlike ordinary major, it has no natural 4 or minor ii chord. The Lydian sound emerges when the major tonic remains the center and #4 is heard as its own modal color rather than as a leading tone into another key.