A modal tune is built on a scale that is one note away from a plain major or minor scale. Bluegrass and old-time players meet two modes again and again. Mixolydian is a major scale with a lowered seventh note. Dorian is a minor scale with a raised sixth note. Both bring a chord players call the flat 7, and that chord is the sound that makes these tunes feel old.
The flat 7 chord
The flat 7 is the major chord one whole step below the 1 chord.
| Key | 1 chord | Flat 7 chord |
|---|---|---|
| A | A | G |
| G | G | F |
| D | D | C |
| E | E | D |
In a plain major key, the 1, 4, and 5 chords do the work. A modal tune swaps in the flat 7, often where you expect the 5. Read the Nashville number system for bluegrass jams.
Mixolydian: major with a lowered seventh
Take the A major scale: A, B, C sharp, D, E, F sharp, G sharp. Lower the seventh note by a half step. G sharp turns into G. That scale is A Mixolydian.
The tune still sounds major, because the third note is C sharp. The G gives it a rough, open edge.
Jam tunes in Mixolydian:
Old Joe Clark, in A. The G chord shows up in the B part.
Red Haired Boy, in A. The chords are A, D, G, and E.
Salt Creek, in A. It uses the same four chords.
Little Maggie, sung in G at many jams. The flat 7 chord is F.
Dorian: minor with a raised sixth
Take the A minor scale: A, B, C, D, E, F, G. Raise the sixth note by a half step. F turns into F sharp. That scale is A Dorian.
The tune sounds minor, because the third note is C. The F sharp keeps it from sounding sad in the usual way.
Jam tunes in Dorian:
Shady Grove, in A. Two chords carry it: A minor and G.
Cluck Old Hen, in A.
How to tell which one you are in
Listen to the third note of the scale.
If the tune sounds major and has a flat 7 chord, it is Mixolydian. The 1 chord is major.
If the tune sounds minor and has a flat 7 chord, it is Dorian. The 1 chord is minor.
Some old tunes sit between the two. The melody slides around the third note, and players disagree about the 1 chord. In a jam, ask the leader: “Is that an A or an A minor?”
Why sheet music looks odd for these tunes
A Mixolydian uses the same notes as D major. Sheet music for Old Joe Clark often shows two sharps, the key signature of D, though the tune is in A.
A Dorian uses the same notes as G major. Sheet music for Cluck Old Hen often shows one sharp.
The home note tells you the key. Both tunes start and end on A.
What each instrument does
Guitar. In A, most players put a capo on the second fret and play G shapes. The flat 7 chord is then an F shape, which sounds as G. Some players skip the capo and play open A and G chords. For Shady Grove in A minor, play open A minor and G with no capo.
Banjo. For Little Maggie in G, stay in open G tuning and reach for the F chord. For tunes in A, capo at the second fret and raise the fifth string to A.
Mandolin. The flat 7 is the same chop shape as the 1 chord, two frets lower. Read mandolin chop chords for every jam key.
Bass. Play the root and fifth of the flat 7 chord. For a G chord, that is G and D.
Fiddle. In A Mixolydian, the G note is a low second finger on the E string and an open G string down low. In A Dorian, add a low second finger on the A string for C natural.
Improvising and breaks
In a break, use the notes of the mode, not the plain major scale. On an A Mixolydian tune, play G natural, not G sharp. A G sharp against the G chord sounds sour.
A safe plan is to play the melody. The melody has the right notes built in.
Calling a modal tune
When you lead one of these, tell the circle about the chord. “Old Joe Clark in A. There’s a G chord in the B part.” For a song, say if the 1 chord is minor: “Shady Grove in A minor.”
Players who do not know the tune will listen for the flat 7 and find it. Read how to lead a fiddle tune in a bluegrass jam and how to call a song in a bluegrass jam.
Hearing the flat 7
Play an A chord, then a G chord, then back to A. That drop and return is the sound. It does not pull toward home the way the 5 chord does. It steps down and steps back up.
Once you know that sound, you will hear it across the room. Read how to hear chord changes in a bluegrass jam.
Practice
Play the A Mixolydian scale and the A Dorian scale, one after the other. Say which note changes.
Play A to G and back, eight times, with a steady beat.
Learn the chords to Old Joe Clark and Shady Grove from their song pages. Both pages have the chord layout, and Old Joe Clark has free sheet music.