C sharp Added Ninth Chord (C♯add9)

1Composition: what it contains

C♯ – E♯ – G♯ – D♯

Symbol

C♯add9

Also written

C♯add9, C♯add2, C♯(add9)

Formula

1 3 5 9

Same sound as

D♭add9

2Appearance: diagrams and sound

On the guitar

On the ukulele

On the piano

On the staff

On bass and as an arpeggio

3Indications: what it is used for

Very popular in pop, rock, worship, singer-songwriter and acoustic styles as a richer version of a major chord on I, IV or V. It adds colour without changing the function of the triad. Guitarists use it in open-string voicings and arpeggiated patterns; pianists use it in ballads and pads. It can replace a plain major chord almost anywhere the melody does not hold the second degree against it. In film music it creates a hopeful, open sound.

4Dosage: how to practise it

On guitar, learn the open shapes (with the ninth on an open or fretted string) and the movable shape rooted on the fifth string; play arpeggio patterns across four strings at 70–90 BPM. On piano, play root-2-3-5 in close position and spread voicings (root-5 in the left hand, 9-3 in the right). Practise progressions like I–V–vi–IV with all chords as add9. Five minutes daily. Compare each add9 with the plain triad and with the sus2 version to train your ear to the presence of the third.

5Warnings and common mistakes

Do not confuse add9 with a ninth chord (9), which includes the flat seventh, or with sus2, which omits the third. The ninth placed directly next to the third (a major second apart) can sound muddy in low registers; voice it higher. 'Add2' usually means the same notes with the second placed within the octave. Avoid doubling the ninth. In strummed guitar parts, make sure the ninth actually sounds and is not muted by a neighbouring finger.

6Interactions with chords, scales and keys

Inversions

• Inversion 1 · C♯add9/E♯ · E♯ – G♯ – D♯ – C♯ Play
• Inversion 2 · C♯add9/G♯ · G♯ – D♯ – C♯ – E♯ Play
• Inversion 3 · C♯add9/D♯ · D♯ – C♯ – E♯ – G♯ Play

Scales to play over C♯add9

• D flat Major Scale
• D flat Lydian Mode
• D flat Mixolydian Mode
• D flat Major Pentatonic Scale
• D flat Major Blues Scale
• D flat Lydian Dominant Scale
• D flat Bebop Dominant Scale

7Other presentations available

The same chord from every note

Cadd9 Dadd9 E♭add9 Eadd9 Fadd9 F♯add9 Gadd9 A♭add9 Aadd9 B♭add9 Badd9

Other chords on C♯

C♯ C♯m C♯dim C♯aug C♯sus2 C♯sus4 C♯5 C♯6 C♯m6 C♯7 C♯maj7 C♯m7 C♯m7♭5 C♯dim7 C♯m(maj7) C♯7sus4 C♯m(add9) C♯6/9 C♯9 C♯maj9 C♯m9 C♯11 C♯m11 C♯13 C♯7♭9 C♯7♯9 C♯7♯5 C♯7♭5