The Many Faces of the D-Major Scale

It’s been said that a single, unaccompanied melody is the intrinsic nature of traditional Irish music.  I agree.  In fact, I apply this basic melody-line philosophy as a starting point to almost all of the tunes I play, whether they are Irish, Appalachian, or something else. 

This doesn’t mean that a single-note melody line should be considered completely devoid of chords, because you can build chords from the ground up based on the notes in the melody and where they fall. (Unless you’re playing bluegrass or jazz, where soloing over chord changes is the norm).

A mode is a selection of tones arranged in a scale which form the tonal substance of a tune*.  Each mode has a tonal center - the first/lowest note of its scale.  Most tunes have a tonal center and will come to rest on that tonal center at certain key points in the melody.  The notes of a tune gain meaning in their relation to this tonal center.

Take the key of the D major (Ionian) scale for example.  The notes are D - E - F# - G - A - B - C# (two sharps).  All of the notes you’ll need to form basic chords are found in that key.  Every note in the melody can be seen as one-third of a potential chord, with that note functioning as either the 1, 3 or 5 of that chord.  (Breaking from that rule - I suppose the G note could be part of an A7 chord at times).

Maid Behind the Bar - D major (two sharps resolving to D)

D is the tonal center of D-major.  So, a D-note in the melody probably indicates a D-major chord (D, F#, A).  This means that D note can be harmonized with another D note, or an F# note or an A note.  There’s also a chance that a D note could be functioning the 3^rd of a B-minor chord (B, D, F#) or as the 5 of the G-major chord (G, B, D), so the notes B and G become additional posibilities.  Let your ear be the judge.

It’s the same thing with an A note in a D-major tune.  That A could be an A-major chord (A, C# E), so you’d select either A, C# or E to harmonize with it.  However, the A could also be the 3^rd of an F#-minor chord (F#, A, C#), or the 5 of the D-chord (D, F#, A). 

Cooley's Reel - E Dorian (two sharps resolving to E)

Additionally, because D is the tonal center you can also use D notes to harmonize as a drone with almost any note in the melody.  So you can see how even if the melody remains exactly the same with no variation there is room for the melody player to improvise with regard to the selection of notes chosen to pair with the melody note to make a double stop (AKA “small chord”, AKA “slant” or “reach”). 

That’s what we mean by the notes of a tune gain meaning in their relation to this tonal center.  If you know a note’s role in the melody, you can eliminate certain unlikely combinations.  For example, a C# note is not going to demand a C# diminished chord (C#, E and G).  That C# note is far more likely to be the 3^rd of the A chord (A, C#, E), although it could be the 5 of the F# minor chord (F#, A, C#) when a minor quality is called for.

Campbell's Farewell to Redgap - A Mixolydian (two sharps, resolving to A)

Quite often in traditional music a tune will be comprised of notes in the D-major scale (D, E, F#, G, A, B, C#) but will have E, A or B as its tonal center instead of D.  When E is the tonal center we call it E-dorian (E, F#, G, A, B, C#, D), when A is the tonal center we call it A-mixolydian (A, B, C#, D, E, F#, G), and when B is the tonal center we call it B-minor (B, C#, D, E, F#, G, A). 

Do not assume that a tune with two sharps is D major (Ionian) or B minor (Aeolian).  It could also be E Dorian or A Mixolydian.  You can hopefully see how each of these different modes use the same notes – but at different starting points – and would have the same chords at its disposal, albeit in different roles. 

Musical Priest - B minor (two sharps resolving to B)

The E-dorian mode is often mistakenly referred to as “E-minor” by Irish music players because it has an E-minor chord (E, G, B) as its root chord, but a true E-minor scale has a C note instead of a C#.  If a tune has a strong need for a combination of an E-minor chord and a D chord – such as Cooley’s Reel or Swallowtail Jig – it’s a sure sign that the tune is in E-dorian and not in a true E-minor aeolian scale like Rights of Man.

Which brings to mind a question I’ve been having lately.  Assuming that you define a non-major mode by comparing it to a major mode, is it better to think of A-mixolydian as the A-major mode with a flattened 7^th note, or as a variant of the D-major mode with a tonal center on the 5^th note (A) of the D-major scale?

Mandolin Finger Patterns of a Major Scale, in this case the D-major scale

On a mandolin, when you place your index finger on a D note, such as the D on the 5^th fret of the 2^nd string, the finger pattern used to fret that D to middle finger E (whole step) to ring finger F# (whole step) to pinky finger G (half step) is the same “whole, whole, half” sequence as placing the index finger on an A note and fretting B, C#, D with the rest of your fingers.  So, “whole, whole, half” when you start with the 1^st note or the 5^th note of a major scale.

A different pattern of “whole, half, whole” emerges when you place your index finger on either the E or B notes within a D-major scale.  A 3^rd pattern of “half, whole, whole” is required when you start on either the F# or C# notes.  Finally, a 4^th pattern of “whole, whole, whole” is used only one time when placing the index finger is on the 4^th note of the scale – G.  You have to really stretch to reach from G to C# on the same string!

I Buried My Wife - D Mixolydian (one sharp resolving to D)

It’s not unusual in Irish music to have a tune with D as its tonal center but feature a C natural note instead of a C#.  The inclusion of the C natural note is an indication that the tune is in D-Mixolydian, not D major.  D-Mixolydian is the same as the G-major scale starting on a D note and/or the D-major scale with a flattened 7th (D, E, F#, G, A, B, C).  D-mixolydian is to G-major as A-mixolydian is to D-major.

*Note: this post was inspired by some information musician Grey Larson had written on a similar subject.  Most of this article is in my own words, but a few sentences are directly taken from his writing simply because he had phrased it so efficiently.

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