Building chords

A chord in relanote is a set of intervals over a root — the same "relative" idea that runs through pitch and rhythm. Define it once with chord, place it on any root, transpose it like any other value.

Defining chords

chord Name = [ ... ] declares a reusable structure. The interior is intervals, starting from R:

chord MajorTriad = [ R, M3, P5 ]
chord MinorTriad = [ R, m3, P5 ]
chord Dom7       = [ R, M3, P5, m7 ]
chord Maj7       = [ R, M3, P5, M7 ]
chord Min7       = [ R, m3, P5, m7 ]

There's nothing magic about the names — MajorTriad is just three intervals. The shape is what's named. Play MajorTriad rooted on C to get C major; root it on G to get G major. The chord doesn't change.

Progressions are scale-degree blocks

A progression is the same block syntax as a melody, only each slot resolves to a chord rooted on that scale degree:

scale Major = { R, M2, M3, P4, P5, M6, M7 }

let I_IV_V_I = | <1> <4> <5> <1> |

Swap the scale to Minor and the same line plays a i-iv-v-i. That's the whole reason we kept everything relative.

Arpeggios

Spell a chord out one note at a time and you have an arpeggio:

scale Major = { R, M2, M3, P4, P5, M6, M7 }

let up   = | <1> <3> <5> <8> |
let down = up |> reverse

Octaves are just another interval — <8> is the scale's eighth degree, which is the root one octave up.

Common shapes

scale Major = { R, M2, M3, P4, P5, M6, M7 }

let pop  = | <1> <5> <6> <4> |             ; I-V-vi-IV
let jazz = | <2> <5> <1> |                 ; ii-V-I

A twelve-bar blues, in the relative-mode equivalent of every other twelve-bar blues ever written:

scale Blues = { R, m3, P4, A4, P5, m7 }

let blues = | <1> <1> <1> <1>  <4> <4> <1> <1>  <5> <4> <1> <5> |

Your turn

Pick a four-degree progression you like (vi-IV-I-V is a useful one to try). Write it once, then transpose it by a few different intervals. Notice that each transposition keeps the same *shape* — the chord relationships don't change, only the absolute pitches do.

scale Major = { R, M2, M3, P4, P5, M6, M7 }

let progression = | <6> <4> <1> <5> |
progression ++ (progression |> transpose P5)

Next: arrange parts, sections and layers in Creating a song.