Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
Calt is C, E, G#, Bb and Db — C7 with every tension it can carry altered at once.
It sounds maximum tension, barely holding together. Not one chord but an instruction: take the root, third and flat seventh, add any two alterations, and let the rest go.

| C | E | G# | Bb | Db |
|---|---|---|---|---|
| 1 | 3 | ♯5 | ♭7 | ♭9 |
Altered dominant — the hardest pull available.
Also written C7alt, C7altered or C altered dominant. The same chord either way; which spelling you meet depends on who wrote the chart.
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
Calt has 6 of them, on the middle four strings, the bottom four strings, the top four strings, strings 5-3-2-1 and strings 6-4-3-2, from the 2nd fret up to the 14th — all in one inversion, so the bass note never moves. The one to learn first is the C shape at the 2nd fret, which is the easiest grip here.
Start with x32x12 — down at the nut. 1 of the 8 shapes here sits in open position. None of them needs a barre. Together they cover the neck from the 1st fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x32x12 | 1st fret | C, root position | Gb | all fretted |
| x32552 | 2nd fret | C, root position | Gb | all fretted |
| x34550 | open position | C, root position | E | 1 open string |
| x34553 | 3rd fret | C, root position | G | all fretted |
| 87x978 | 7th fret | C, root position | C | all fretted |
| x-x-10-9-7-8 | 7th fret | C, root position | C | all fretted |
| 8-9-10-9-x-8 | 8th fret | C, root position | C | all fretted |
| x-x-10-11-13-12 | 10th fret | C, root position | E | all fretted |
The same notes rebuilt from scratch give 14 rootless voicings, each on its own page.
Tensions. A shell of Calt, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (F#).
Calt is a dominant with its tension raised, so it still points at F — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, Calt → F. 4 voices move by a semitone, and one note is common to both chords.
| In Calt | Moves | In F |
|---|---|---|
| C, the root | stays where it is | C, the fifth |
| E, the major third | rises a semitone | F, the root |
| G#, the sharp fifth | rises a semitone | A, the major third |
| Bb, the flat seventh | falls a semitone | A, the major third |
| Db, the flat ninth | falls a semitone | C, the fifth |
Every note of Calt is in C altered.
Change one note of Calt and you have Caug7 (drop the flat ninth), Caug9 (the flat ninth becomes a ninth) or C7b9 (the sharp fifth becomes a fifth).
Calt is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On Calt’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.