Chords » Bb Augmented Major 7th

Symbols:Bb+Maj7, BbaugM7, BbaugMaj7
Scale Degree Formula:1-3-#5-7
Interval Stack:M3 + M3 + m3
Notes:Bb, D, F#, A
Hear this chord:▸ Guitar

Construction

Using the scale degree formula, we first start with the Bb major scale, and number each note in the scale starting from 1 - these are the scale degrees. Next, we use the scale degree formula, in this case 1-3-#5-7, to select notes from our enumerated scale. When a chord requires notes that are not in the scale, this is indicated with a flat (♭) or a sharp (#) along with the scale degree; a ♭3, for instance, would be one half-step down from the 3rd scale degree.
Alternatively, we can use the interval stack to construct our chord. With this approach, we first start with the lowest note of the chord (Bb), then move our first interval (M3), which brings us to our second note in the chord (D). We repeatedly apply each of the remaining intervals in the stack to get the full list of notes for our chord.
The diagram below shows how both the scale degree formula and interval stack methods result in the same selection of notes:
Bb1B♭2C2C#♭3D3D#4E♭5F5F##5G6G#♭7A7M3M3m3

Frequencies and Harmonics

On acoustic instruments (such as guitar or piano), a single played note will result in more than a single sounded frequency. There's a lot of complexity here, but at its simplest, the fundamental (eg: A4 = 440Hz) will sound, as well as a number of harmonies, which are multiples of that frequency.
The graph below presents a simplied representation of the sounds and relative amplitudes that are sounded when this chord is played. The exact instrument, and even how the chord is played, can vary things dramatically, but this can give you an understanding of certain sounds you may hear when playing a chord.
Each fundamental and its harmonies are given a different color. The height of the bar represents the amplitude (volume) of the frequency, and the position (left-to-right) represents the frequency of the sound (further to the right means higher). Finally, the grid-lines represent notes in 12-tone-equal-temperment (notes used in traditional western music).
frequencyamplitudeC2C3C4C5C6C7
From these frequencies, we can determine harmonics that sound when we play the notes of a chord. These harmonies are listed below, along with the frequencies contributing to each. It's worth noting that these frequencies won't all be the same for higher harmonies, and some harmonies will be flat, sharp (or both).

Primary chord notes

These 'harmonics' are the primary notes of the chord.
A
Frequencies (HZ):220, 440, 440, 880, 881, ...
Intonation:In tune
Bb
Frequencies (HZ):117, 233, 466, 925, 932, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -14 to 0.
D
Frequencies (HZ):147, 294, 583, 587, 1165, 1175, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -14 to 0.
F#
Frequencies (HZ):185, 370, 734, 740, 1468, 1480, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -14 to 0.

Significant harmonics

Harmonics with a prominent presence in the chord.
C#
Frequencies (HZ):555, 1100, 1110, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -14 to 2.
E
Frequencies (HZ):660, 1282, 1295, 1320, 1321, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -49 to 4.
F
Frequencies (HZ):350, 699, 1398, ...
Intonation:In tune

Lesser harmonics

Harmonics that are less prominent, but present nonetheless.
C
Frequencies (HZ):1028, 1049, ...
Intonation:Mixed — Sometimes flat, sharp, or in-tune. Cents off range from -31 to 4.

Similar Chords

The following chords are similar to this chord and may be a suitable replacement in certain scenarios.

Chord TypeChords
Added 9thDadd9
AugmentedF#aug, Daug, Bbaug
Diminished Major 7thD#dimMaj7
Dominant 7thD7
Dominant 7th Flat ThirteenthD7b13
Dominant 7th Sharp FifthF#7#5, D7#5, Bb7#5
Dominant 7th Sharp Five Sharp 9thF#7#5#9
MajorD
Major 2ndD2
Major 6thDM6
Major 7thDM7, BbM7
Major 7th Flat FifthBbMaj7b5
Major 7th Flat ThirteenthDMaj7b13, BbMaj7b13
Major Added 11thDadd11
Minor 2ndGm2
Minor 7thBm7
Minor Added 9thGmadd9
Minor Major 7thGmM7, D#mM7, BmM7
Minor Major 9thGmMaj9

Associated Scales

This chord can be found in the following scales.

ScaleRoots
Dorian b5E, C
Harmonic MajorD, Bb
Harmonic MinorG
Ionian #5Bb
Locrian bb7A, C#
Locrian ♮6A
Lydian #9D#
Lydian Augmented #2F#, Bb
Lydian b3G, D#
Mixolydian b2A, F
Phrygian DominantD
Phrygian b4F#, D
Super-Locrian bb7F#
Ukrainian DorianC

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