Presentation courtesy of Squiggle Theory
Motivation
“Nashville” numbering for chords amounts to a movable solfege, in that it is key-free, key-agnostic, key-generalized. Studio musicians and multi-instrumentalists typically are familiar with using numbers 1..7 as chord root designators, inflected as necessary with sharp or flat. What with added degrees and characterizations superscripted (min, m, maj, ma, aug, dim, sus, …) and slash chords, this makes for some wordy chord indications.
This proposed convention erects five single-letter main designators to stand for the inflected forms. It eliminates such complexities as “flatted .3” in A not being a black keyboard note.
Z-Modal Music
Since Nashville departs from Rameau floating modal tonic convention (6 tonic for minor, 5 tonic for mountain, e.g.) by treating tonic as 1 regardless of mode, the designations 1mi, 1m and 1– for 1-minor are seen (minor, dorian, phrygian).
In much music, the flatted seventh degree is prominent in practical chord-root use. It arises in mountain (mixolydian), dorian and natural minor (aeolian), as well as the less frequent phrygian. (Lydian and locrian are “right out” [Monty Python or somebody].) Indeed, in folk music such as ballads, sea chanties, and modern compositions in their genres, a bi-centric chord structure of tonic and sub-tonic is seen in contrast to more modern tri-centric 1-4-5. There is a large body of bi-centric music with 1-Z (mountain: Old Joe Clark) or 1m-Z (dorian: Scarborough Fair, Shady Grove, Drunken Sailor) or 1m-Zm (phrygian) chord structure. The quickly recognizable similarity in sound from this simpler chord root alternation comes from their being Z-modal.
Example
The example is in slantnote-on-rails. Rails are tonic and dominant; leger lines likewise. Tonic top and bottom is authentic lie, as here. Plagal lie puts tonic rail between two dominant rails The “Three Blind Mice” 3-2-1 footprint indicates the mode.
Mnemonics
The glyph for 7-flat is Z, visually related to the numeral. The other glyphs are likewise chosen for mnemonic convenience. The J for 6-flat/5-sharp is a hook mirror-imaging 6. The Q between 4 and 5 reflects the Latin words for those numerals (quartus, quintus). Also, imagining Q as “split O” evokes splitting the “full circle” Octave quite in half, for that “Queer” tritone sound.
The degree between 2 and 3 is more usually related to 3 (blues, e.g.), so M is proposed: 3 rolled over onto its legs (with its joints angularized). A further mnemonic hook is that the alteration creates a Minor tonality. For european-trained musicians, M bespeaks moll (minor). Such a musician is apt to say “soft” in English instead.
For the 2-flat/1-sharp degree I chose T. “Tea for Two-flat” or, for the other context, 1 with “something extra” on it. Constraining these choices was a concern for avoiding conflict with musical directions that may likewise appear above a staff, such as P, V (up-bow), X (pitchless note), and so on.
Squiggle Schema Above
The squiggle diagram above, on which these extensions and the 1..7 main chord designators are schematized, is the basis for Slantnote, an alternative music notation system.
— “Slantnote” (David Zethmayr), 22 November 2011