Diatonic chords — why it is not always 0 3 7

A triad = root + a third + a fifth, but "a third" comes in two sizes (minor +3, major +4) and the fifth is usually +7, sometimes +6 or +8:

Build a chord on every note of a scale using only scale notes and the formula changes per degree. In C major:

Typing 0 3 7 on every note of C major would put out-of-scale notes into the chords on C, F and G. These in-scale chords are diatonic chords; 037-lab computes them for any scale and highlights every adjusted digit (source: s-037-lab). For a chord-arpeggio this is the difference between an arp that fits and one that clashes.

In scale degrees and stacked thirds (TraxWeekly)#

The scene's own formulations agree with the table above. Leviathan (1995) writes chords as scale degrees: Major 1 3 5 · Minor 1 3b 5 · Add2 1 2 3 5 · Sus2 1 2 5 · Sus4 1 4 5 · Fifth 1 5 · Minor 7 1 3b 5 7b · Major 7 1 3 5 7 · Diminished 1 3b 5b (C minor 7 = C D# G A#), and advises keeping every chord of a progression inside one mode so leads write themselves (source: s-tw001-modal-and-chord-theory). Greg Heo (1997) explains why the formulas differ: a major triad is a major third plus a minor third spanning a perfect fifth, a minor triad the reverse; augmented (+4 +4) and diminished (+3 +3) do not span a perfect fifth and sound "funny"; consonant intervals are the perfect ones (P1, P8, P5, P4) and the imperfect ones (M3, m3, M6, m6), everything else is dissonant (source: s-tw074-intro-to-musical-theory). The Modsquad's list adds ninths and elevenths (Maj9 C E B D, Min9 C D# A# D, Min11 C D# A# F, Maj add9 C E G D) with the tip to use the same instrument for every note of a chord (source: s-tw077-chip-off-the-block).

Spelling any chord from interval qualities (Zinc, 1997)#

Zinc's "Layman's Music Theory" gives the recipe behind the tables: a chord is two or more notes together, a triad has three, the root is the note it is built from, and the chord type is fixed by the intervals from the root — every major triad has a major third (M3) and a perfect fifth (P5). Lower the M3 a half step and it becomes m3 (minor); shrink the P5 and it is diminished, stretch it and it is augmented. His worked example: F#m = F# + a minor third (1½ steps = 3 semitones → A) + a perfect fifth (3½ steps = 7 semitones → C#), i.e. 0 3 7 from F# — "It works!" Scale degrees continue past the octave (9 = D, 11 = F, 13 = A above C), which is where ninth and thirteenth chords get their names (source: s-tw107-laymans-music-theory).

Beyond triads#

0 4 7 10 dominant 7 · 0 3 7 10 minor 7 (instant funk/jazz) · 0 4 7 11 major 7 · 0 3 6 10 half-diminished · 0 3 6 9 dim 7 · 0 4 7 9 major 6 · 0 3 7 9 minor 6 · 0 4 7 14 add 9. Replace the third for suspended chords: 0 5 7 sus4, 0 2 7 sus2 — neither major nor minor, great for tension before resolving. Drop the third for a power chord 0 7. necros's 1995 voicing lesson shows the extensions at work in a plain I–IV–ii–V: C9 (C G C D E), Fadd2 over C, Dm7 and a Gsus4 that resolves to G — the spellings and the voice leading are on chord-inversions (source: s-tw018-advanced-tracking-tips-iii).

The app's data expresses each chord as which scale steps it stacks (triads stack degrees 0 2 4; sevenths 0 2 4 6; sus2 0 1 4; sus4 0 3 4; add9 0 2 4 8), which is what makes the snapping work for any scale length.

What you can actually type#

A chord formula is one thing; the number of notes the tool will let you name in one place is another, and on chips they rarely match.

• lsdj Cxy takes exactly two offsets, so a chord command is always three notes: C37 minor, C47 major. A four-note chord — 0 4 7 10 dominant 7, 0 3 7 10 minor 7 — does not fit and has to go in the instrument's table transpose column or onto a second channel (source: s-lsdj-manual; instrument-tables).
• impulse-tracker Jxy and MOD/XM 0xy have the same three-note shape — "the note playing, a note x halftones above, and a note y halftones above" — and one hex digit each, so no offset above +15 (sources: s-it-manual, s-tw074-intro-to-musical-theory). Zinc's compound intervals (9th = 14, 11th = 17, 13th = 20) are therefore out of reach of the command and have to be voiced across channels.
• sid-wizard takes the chord out of the instrument entirely: chords live in their own table, selected per pattern row (instrument column $7x, big effect $07) or reached from a wave-table ARP row with $7F, "so you don't have to create different instruments for different chords". Chord length is a table length, not a command width, and the editor will show the values as note names or numbers (C=+N) and negate one with = (source: s-sid-wizard-charts-and-tables).
• goattracker and sid-factory-ii have no chord command at all: a chord is rows of a wavetable, one semitone offset per row (sources: s-goattracker-readme, s-chordian-sf2-instruments).

So the practical order of questions is: spell the chord in semitones, check whether the tool can say it in one place, and if not decide which note to leave out or which channel to spend — the voicing question that chord-inversions answers with Necros's worked example.

Is a chord even a thing?#

Worth recording, because the scene argued about it for four issues in 1995–96. trixter: "A chord isn't a 'thing', it's any combination of notes" — every piece of music has chords, ambient is "one long, ever-changing chord", and the only chord-less music is deliberately monophonic. maelcum's counter is that chords are "a valid and valuable tool" but necessary only for certain kinds of music. basehead narrowed the real claim to whether theory helps, not whether chords exist (source: s-tw039-chord-theory-debate). The tables on this page are a vocabulary, not a rule.

Related#

chord-inversions · chord-progressions · scales-and-modes · chord-arpeggio · semitone-math · instrument-tables

Sources#

s-037-lab · s-tw001-modal-and-chord-theory · s-tw074-intro-to-musical-theory · s-tw077-chip-off-the-block · s-tw107-laymans-music-theory · s-tw018-advanced-tracking-tips-iii · s-tw039-chord-theory-debate · s-lsdj-manual · s-it-manual · s-sid-wizard-charts-and-tables · s-goattracker-readme · s-chordian-sf2-instruments