A# major
Major key. Scale: A#, B#, D, D#, E#, G, A.
Octaves
Musical context
How the key relates to the chord, scale, mode and progression.
Theory
General info
- Name
- A# major
- Mode
- Major
- Tonic
- A#
- Key signature
10 sharps: A, B, D, E.
- Key character
- Scale degree 3 clearly distinguishes major from the parallel minor, while the leading tone strengthens V–I resolution. In equal temperament, tonic pitch alone does not determine mood; melody, harmony, register, tempo, and texture do.
- Overview
- The A# major key sets its stable tones and typical harmonic connections. Major keys are built on the Ionian mode (steps 2 – 2 – 1 – 2 – 2 – 2 – 1), minor keys on the Aeolian (2 – 1 – 2 – 2 – 1 – 2 – 2). The number of accidentals marks the key's position on the circle of fifths.
Key composition
1A#root
2B#major 2nd
3Dmajor 3rd
4D#perfect 4th
5E#perfect 5th
6Gmajor 6th
7Amajor 7th
Key construction
- Interval formula
- A#WB#WDHD#WE#WGWA
- Explanation
- The major scale follows the pattern whole, whole, half, whole, whole, whole, half. Its degrees form the key’s diatonic chords, while scale degree 3 defines the major quality.
Related keys
- Relative key
- G minor
- Parallel key
- A# minor
- Reference mode
- A# Ionian (major)
Harmonic functions
TTonicI (A#), IV (D#)
SSubdominantIII (D), vi (Gm)
DDominantVII (A)
- Overview
- Tonic is the stable centre of a key. Predominant function moves away from tonic and prepares dominant; dominant points toward resolution in tonic. The scheme Tonic → Predominant → Dominant → Tonic describes a basic functional progression but does not exhaust tonal harmony.
Chords by degree
Primary triads
- Tonic triad 1 – 3 – 5
- Subdominant triad 4 – 6 – 1
- Dominant triad 5 – 7 – 2
A#—D—E#
G—A#—D
A—B#—D#
Tensions & resolutions
VIIAA
IA#A#
In typical voice leading, the leading tone rises by semitone to tonic.
IVD#D#
IIIDD
In dominant harmony, scale degree 4 normally falls by semitone to 3.
IIB#B#
IA#A#
Scale degree 2 may resolve downward by step to tonic.
Harmonic context
A# major is a major key. Diatonic chords are built on its seven scale degrees, and functional motion commonly connects tonic, predominant, and dominant.
Natural progressions
Cadences
VAA
IA#A#
An authentic cadence resolves dominant function into tonic.
IVGG
VAA
IA#A#
A complete functional progression connects predominant, dominant, and tonic.
This key on guitar 🎸
See how A# major looks on guitar.
Circle of fifths
Usage & Practice
Application in music
- Major-key diatonic chords support motion among tonic, predominant, and dominant without leaving the key.
- The authentic V – I progression emphasises the tonal centre through the leading tone and resolution of the dominant tritone.
- Patterns such as I – V – vi – IV can be transposed into this key without changing scale-degree relationships.
- Musical character depends not only on mode and tonic but also on melody, rhythm, register, tempo, texture, and timbre.
Practice
- Play the tonic chord (A#), then compare it with the other diatonic chords: tonic serves as the stable centre of the key.
- Alternate A# and A (I – V – I), focusing on the leading tone resolving to tonic.
- Add Gm (IV): play Gm – A – A# to hear predominant–dominant–tonic motion.
- Sing the key's scale, emphasizing degrees I, III and V — these are the anchor notes.
- Improvise a melody starting and ending on the tonic to reinforce the sense of center.
Keyboard Trainer
Reinforce it in practice — play and name notes on the interactive keyboard.