Just what is the mysterious Steely Dan mu (µ) major chord?
Read my article "The Birth of the Mu Major Chord" which describes the first documented use of the chord in 12th century Paris (article hosted on Mizar6 website).
There are two main types of mu major chord:
The first type is the classic "early period" (pre Royal Scam) mu major, the latter is usually found in the later albums such as Aja and Gaucho. Each of these two types can be voiced in several different ways.
The most common Steely Dan mu major voicings are described below. The voicings are "spelled out" starting from the lowest note and moving up to the highest note, either using degrees of the scale (e.g 1st, 5th, 2nd, 3rd) or note names (e.g A E B C#).
Note that mu major chords must have at least four notes, but if one or more of the constituent notes are used twice, mu major chords with five or more notes can be created.
Mu chords with five or more notes do appear in some Steely Dan songs, but their sound tends to be a little more rich and lush. The typical Steely Dan mu major chord uses four notes, with a sparser sound and tighter jazz-like voicings. All the examples given below relate to the more common four-note mu major chords.
The type I mu major chord has the root in the bass. Looking at the most common four-note mu major, there are three ways to voice this chord. Two of these voicings have the second and major third next to each other creating a slight dissonance, and it is these two dissonant voicings that are nearly always used whenever a type I mu major chord appears in a Steely Dan song.
But hey, don't take my word for it! Read what Donald and Walter wrote about the mu major some years ago:
Voicing A (basic voicing): 1st, 2nd, 3rd, 5th
Here the 2nd and 3rd are next to each other adding a dissonance to what would otherwise be a plain, consonant major chord. In most cases, there will be a gap of just over an octave between the bass note and the lowest note of the triad.
Examples of type I mu (basic/voicing A)
Voicing B: 1st, 3rd, 5th, 2nd
Here, the triad at the top of the chord is in its first inversion. This means that the second and third are separated, so they do not give a dissonant effect, and the resulting chord has a more open sound. Because the more dissonant or "clustered" sound of the mu major is usually favoured, this voicing is rarely used in Steely Dan songs.
Examples of type I mu (voicing B)
Voicing C: 1st, 5th, 2nd, 3rd
Here, the triad at the top of the chord is in its second inversion, which means the 2nd and 3rd are right next to each other (as with voicing A). This gives the characteristic dissonant touch to the basic major sound that is typical of the Steely Dan type I mu major.
Examples of type I mu (voicing C)
The type II mu major chords have the 3rd in the bass, giving them a distinctly different sound to the type I mu majors. Type II mu majors became the more common Steely Dan mu for later albums (Royal Scam, Aja, Gaucho).
For type II mu majors with four notes (as with type I mu majors) there are three possible voicings, but nearly all of the type II mu chords used in Steely Dan songs use the same "classic" voicing.
Classic voicing: 3rd, 2nd, 5th, 1st
Voicing the mu major chord in this way separates the 2nd and 3rd and removes the interesting dissonance that is the main feature of the type I mu majors. Instead, this voicing of the type II mu-major sounds more open and jazzy. Note that you get two stacked 4ths at the top, contributing to the jazzy sound of the chord. This particular voicing of the mu-major chord is perhaps one of Steely Dan's most characteristic harmonic devices.
Examples of type II mu (classic voicing)
So why do the songbooks always call this chord m7#5?Whenever the type II mu major appears in one of the Steely Dan songbooks, it is almost always called a m7#5. Now, the naming of chords is always somewhat subjective, but to me this name denies the essential mu majorness of the chord. To my ears, the chord's function and sound is very closely related to a major chord with the third in the bass. Using a name such as Asus2/C# emphasises the similarity to the inverted major chord (A/C#) and makes perfect sense to me, but obviously not to the people who produce the songbooks.
Other voicings of the type II mu major chord are possible but are rarely used in Steely Dan songs. A few examples are given below:
Previous: Mu major Part 1
Next: Mu major Part 3
Last updated: February 2017
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