C#9sus4 Piano Chord

Piano Diagram of C#9sus4 in Root Position

The C#9sus4 chord is a suspended dominant 9th chord built upon the key of C-sharp. It’s made by the root note C#, the perfect 4th F#, the perfect 5th G#, the minor 7th B, and the major 9th D#. Keep reading to gain a deeper understanding of the music theory behind this chord.

 

You can start by playing the root note C# with your left hand. Then, with your right hand, you can play the 4th F#, the minor 7th B, and the 9th note D#. You can add the 5th, G#, to get a little bit of dissonance.

C# + F# B D#

This will result in a simplified C#9sus4 chord that consists of the root note, perfect 4th, minor 7th, and the 9th notes only.

Another simple way to voice this chord is to play the root note with your left hand and a G# min7 chord with your right hand.

C# + G#m7 =

C# + (G#, B, D#, F#) =

C#9sus4

This voicing is essentially the second inversion of a 9sus4 chord without the root note, which is equivalent in sound to a minor 7th chord built on the 5th note from the root.

 

C#9sus4 Chord Inversions

 

The C#9sus4 chord has a total of 4 inversions:

Piano Keyboard Diagrams

Chord Inversions on Piano

While chord inversions are a fundamental concept in music theory, the diagrams that show the sequence of notes in a complex chord on a piano keyboard may not necessarily be practical for playing. This is because proper chord voicings involve distributing the notes of the chord across different octaves and positions on the keyboard. This can be very different from the basic shape of the chord’s inversions. Therefore, the diagrams of chord inversions are mainly intended to show the sequence of notes on the piano keyboard for music theory purposes, rather than for practical playing.

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Music Theory and Harmony of C#9sus4

What are Suspended  Chords?

Suspended chords are a type of chord where the third note is replaced by either a major second or a perfect fourth. This creates sus2 and sus4 chords, which have a unique and sometimes unresolved sound that adds tension and interest to music. These chords can be used as substitutes for major and minor chords because of their neutral nature.

The 9sus4 chord is a more intricate version of the sus4 chord, featuring a minor 7th and 9th note in addition to the perfect fourth. This chord is commonly used in jazz and blues music to add complexity and interest to chord progressions. It is often used as a substitute for dominant 7th chords. Read on to learn how to build a C#9sus4 chord, or scroll down to see where it can be used in different keys and degrees.

 

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Building the C#9sus4 Chord: Different Approaches

Starting from a Major Scale

To create a 9sus4 chord, you can use the Major scale as a reference by combining a Root, a 4th, a 5th, a minor 7th, and a 9th.

In this case, to build a C#9sus4 let’s start from the C# Major scale, which includes the notes C#, D#, E#, F#, G#, A#, and B#.

 

 

 

Apply the formula R, 4°, 5°, m7°, 9° to get a C#9sus4 chord.

1. Select the Root note, which is C#.
2. Pick the 4th note, which is F#.
3. Add the 5th note, which is G#.
4. To add the 7th note, we need to use a minor 7th interval, which means we must use a flat seventh. In the C# Major scale, the 7th note is B# (C), so the minor 7th is B.
5. Lastly, include the 9th note of the C# Major scale, which is D#.

 

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by Combining Intervals

To build a 9sus4 chord, you can stack together a perfect 4th, a whole-tone (or major 2nd), a minor 3rd, and a major 3rd.

4 + 2 + m3 + 3 = 9sus4 Chords

In fact, when building a C#9sus4 chord, you can see that C#-F# is a perfect 4th, F#-G# is a major 2nd, G#-B is a minor 3rd, and B-D# is a major 3rd.

 

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How to Use C#9sus4 in a Chord Progression

 

Suspended chords have a unique quality that sets them apart from major and minor chords. They are neither major nor minor, which makes them a useful tool for creating tension and suspense in a musical composition before resolving to a stable major or minor chord.

To use a C#9sus4 chord in a chord progression, you can refer to the following tables, which show the most common positions where the chord can be found or used. However, it’s important to note that, since this chord features a minor 7th, it cannot be used with Maj7 chords, such as sus2 or sus4 chords. Nonetheless, it can be used on dominant chords and in all positions where a C# min7 is present.

C#9sus4 as Substitute of C#7

C#9sus4 can be used as a substitute for C#7 in major and minor keys. In F# major, C#7 can be replaced with C#9sus4 in the V position. Similarly, in the D# minor key, C#7 can be substituted with C#9sus4 in the VII position.

 

on Major Scales

• Dominant chord in F# Major

 

on Natural minor Scales

• Leading tone chord in D# minor

 

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C#9sus4 as Substitute of C# min7

C#9sus4 chord can be used as a substitute for C# minor 7th chord in various major and minor keys. Note that in the key of A Major and F# minor, D# can clash with the D notes that are part of those keys. While this doesn’t prevent you from using the C#9sus4 chord in those positions, it’s important to be aware that it can create a strong dissonance with the melody or other elements of the composition.

 

on Major Scales

• Supertonic chord in B Major
• Non Diatonic Mediant chord in A Major
• Submediant chord in E Major

 

on Natural minor Scales

• Tonic chord in C# minor
• Subdominant chord in G# minor
• Non Diatonic Dominant chord in F# minor

 

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C#9sus4 Chord Function in Major and Minor Keys

Understanding Scale Degrees

When creating chords from a scale, each note in the scale is assigned a degree, which reflects its position in the scale. In the diatonic major scale, there are seven degrees, and each degree has a unique role in the overall harmony of the scale.

1. The first degree of the scale is called the Tonic, and it serves as the foundation for the scale. It provides a stable tonal center and is often referred to as the “home base” of the music.
2. The second degree of the scale is called the Supertonic. It’s typically used as a passing note between the tonic and other scale degrees, and it adds a sense of movement to the melody or harmony.
3. The third degree of the scale is called the Mediant. It’s located halfway between the tonic and dominant notes and helps to establish whether the scale is major or minor.
4. The fourth degree of the scale is called the Subdominant. It’s often used as a complementary harmony to the dominant and adds a sense of tension and resolution to the music.
5. The fifth degree of the scale is called the Dominant. It generates tension and a sense of expectation, and it’s typically resolved by returning to the tonic.
6. The sixth degree of the scale is called the Submediant. It’s often utilized as a transition between the dominant and tonic, and it provides a sense of stability and restfulness to the music.
7. The seventh degree of the scale is called the Leading tone. It’s located one half step below the tonic and produces a strong sense of tension and a desire to resolve to the tonic. It’s often used to create a sense of resolution and finality in the melody or harmony.

 

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C#9sus4 in F# Major

When playing in the key of F# Major, the fifth degree of the scale is C#7. However, substituting it with a C#9sus4 chord can introduce a feeling of anticipation and suspense, which can be resolved by returning to the dominant chord or by moving to another degree of the scale.

 

C#9sus4 as V degree – Chord Progressions

ii V I

You can experiment with different ways of playing the C#9sus4 chord in the key of F# Major. For example, you could play just the C#9sus4 chord, or split the measure in half and play both the C#9sus4 and C#7 chords. Another option is to invert the order of the chords, playing the C#7 chord first and then resolving to the C#9sus4 chord.

I IV V

 

 I V vi IV

 

I IV vi V

 

 I IV ii V iii vi ii V

 

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C#9sus4 in D# Minor

In the D# minor key, the seventh degree of the scale features a C#7 chord. By incorporating a C#9sus4 chord in this position, you can generate a feeling of expectation and tension, which prepares the listener for the eventual resolution to the tonic chord. You can experiment with playing just the C#9sus4 chord or combining it with the C#7 chord.

 

C#9sus4 as VII degree – Chord Progressions

i VI VII

 

i v VI VII

 

i III VII VI

 

Circle Progression

 

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C#9sus4 in B Major

In B Major, the second chord of the scale is typically a C# minor. However, substituting it with a C#9sus4 chord can introduce some color and tonal intrigue to a chord progression.

 

C#9sus4 Chord Progressions as ii degree

ii V I

 

I IV ii V iii vi ii V

 

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C#9sus4 in A Major (Non Diatonic)

When playing in A Major, you can use the C#9sus4 chord as a non-diatonic substitution for the C# minor chord on the III degree. However, it’s essential to note that the C#9sus4 chord includes a D#, which may clash with the D note present in the A Major scale.

 

C#9sus4 Chord Progressions as iii degree

I iii IV V

 

I iii ii V

 

I iii vi IV

 

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C#9sus4 in E Major

In the key of E Major, you can use the C#9sus4 chord as a replacement for the VI degree chord, where a C# minor chord would typically be played.

 

C#9sus4 as vi degree – Chord Progressions

I iii vi V

 

I vi ii V

 

I IV ii V iii vi ii V

 

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C#9sus4 in C# Minor

In the key of C# minor, incorporating the C#9sus4 chord can add variation to the traditional C#m chord typically used in the key.

 

C#9sus4 Chord Progressions as i degree

i VI VII

 

i iv VI VII

 

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C#9sus4 in G# Minor

When playing in the key of G# minor, you can try using the C#9sus4 chord as a substitution or variation for the C# major chord on the IV degree.

 

C#9sus4 Chord Progressions as iv degree

iv III VI VII

 

i iv VI v

 

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C#9sus4 in F# Minor (Non Diatonic)

In the key of F# minor, you can use the C#9sus4 chord as an alternative or substitution for the v degree chord (C# minor chord). However, it’s important to note that the C#9sus4 chord contains a D#, which is not diatonic to the F# minor scale that includes a D. As a result, it’s generally recommended to avoid using the C#9sus4 chord in this context, but it’s worth experimenting to see if it suits your desired sound.

 

C#9sus4 as v degree – Chord Progressions

i iv VI v

 

i v VI VII

 

i VI v iv

 

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9sus4 and 11th Chords: Similarities and Differences

9sus4 chords share almost the same notes as 11th chords. The only difference is the presence of the 3rd in 11th chords.

C#9sus4 = C#, F#, G#, B, D#

C#11 = C#, E#, G#, B, D#, F#

However, it is important to note that a 4th is not the same as an 11th, even if they are the same note. There is an octave of difference between them. This distinction may not matter when playing an inversion of the chord, but it is still important to be aware of.

 

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Alternative C#9sus4 Chord Nomenclature

• C#9 sus4
• C#7^(9sus4)
• C#9sus 4th
• C# nine suspended 4th
• C# ninth suspended fourth
• C# Dominant ninth suspended 4

 

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