The Avoid Note

The F over Cmaj7

Cmaj7 is C, E, G and B. A half step above each of those sits C♯, F and A♭. Those three pitches are the ones that will rub against the chord if they are held inside it, and F is the famous one, because F is the fourth degree of the scale the chord came from.

So a rule that seems perfectly reasonable — a scale containing a half step above a chord tone is not a fully consonant choice — puts C Ionian outside the innermost circle of scales for Cmaj7. C Lydian, which raises that F to F♯, passes cleanly. Arithmetically the rule is doing exactly what it was written to do. Musically it has just told a player that the major scale is a slightly outside colour over the major seventh chord.

When a formalisation contradicts every practising musician at once, the formalisation is what is wrong. The interesting question is which part of it — and answering that turns out to be more valuable than the patch.

What the theory world actually says

Four bodies of writing bear directly on this, and they agree more than they appear to. None of them uses the avoid note the way a naive rule does.

Jamey Aebersold — the Scale Syllabus

The Scale Syllabus is the closest thing the tradition has to a ranked list of scales per chord. Its stated ordering principle is that each category begins with the scale most closely resembling the chord symbol, and continues in order of increasing dissonance. For the major family it opens with Ionian, then Lydian.

Read that carefully: the scale containing the avoid note is printed first, and the scale that removes the avoid note is printed second. The F is not a demotion at that level of description at all. Where Aebersold does mention the fourth over a major chord, it is as a passing tone rather than a resting point — a caution about use, never about membership.

Berklee — Nettles & Graf

Three words in that sentence carry the whole argument.

“Of a chord scale.” An avoid note is a property of a scale in its role as the chord's scale. You cannot have one without having first accepted the scale as belonging to the chord. The term presupposes membership; it cannot be used to revoke it. C Ionian is the chord scale of Cmaj7 — F is its avoid note precisely because of that, not in spite of it.

“Harmonically.” The restriction is on the voicing: do not put F inside the chord. It is not a restriction on the melody. Avoid notes are played constantly, as passing and neighbour tones. Berklee's own teaching phrase for the marking is handle with care.

So Berklee supplies both halves at once: a precise detector for the interval, and an explicit statement that the detector is a caution, not a gate. A rule that treats it as a gate has taken a diagnosis and printed it as a verdict.

This is the melodic half of a distinction whose harmonic half is already written down: the Chord Naming Law keeps the natural eleventh out of the chord's name over a major third, for exactly the reason Berklee gives. The same interval, refused in the voicing and welcomed in the line.

Mark Levine

Levine weakens the framing further. He treats the fourth as a passing tone, and he is broadly unsympathetic to the word “avoid” at all — in jazz voicing practice nearly any note finds its way into a harmony, and the F over C reappears as an ordinary eleventh once the stack reaches into the second octave. His practical teaching is that the note is fine wherever it moves and questionable only where it sits.

That sit-and-move distinction turns out to be the useful axis, and — this is the part worth noticing — it is not measured by the avoid note at all. It is measured by how much of the chord a collection actually states. A seven-note scale is a vocabulary you travel through. A five-note collection is closer to a colour you sit in. The thinness is the cause; the avoid note merely happened to correlate.

George Russell — the Lydian Chromatic Concept

Russell inverts the ranking on principle. Built by stacking perfect fifths from the tonic, Lydian is for him the most vertically unified scale, and therefore the true parent of the major chord, with Ionian a derived and less unified ordering. He grades everything on a ladder from ingoing to outgoing — a tier system, arrived at by tonal gravity rather than by counting avoided notes.

Aebersold and Russell do not contradict each other about tiers. They differ about a tiebreak: resemblance to the written symbol, or vertical unity. Both are defensible, which is a good reason to expose the choice rather than bury it.

Two measurements, and one marking

The formulation String Logic works from separates three things that a single avoid-note rule had collapsed into one. Each measures exactly one thing, and only two of them decide rank.

Ranked in that order — coverage, then how few foreign tones, then how little the collection alters the plain reading of the written symbol, then the avoid-note weight — the tiers fall out where the books put them, and the tiebreak Aebersold and Russell disagree about is a single preference rather than a second law.

Seven collections over Cmaj7

The same chord, the same seven candidates, measured rather than asserted. Chord tones: C, E, G, B. Half steps above them: C♯, F, A♭.

Within a rank the order runs by coverage first. C Ionian and C Lydian tie on every count except one: Ionian alters nothing away from the plain reading of “Cmaj7”, and Lydian alters one degree.

C Ionian sits at the top, carrying its warning rather than its exile. F major pentatonic lands in the colours — and it lands there because it says only two of the four chord tones, not because of its F. B minor pentatonic keeps it company with no avoid note anywhere in it, which is the honest result: the two collections are thin in the same way, and the avoid note was never what made them thin.

The B♭ that no avoid-note rule can see

B♭ major pentatonic over Cmaj7 is the row that repays the whole exercise.

Ask an avoid-note rule about it and the answer comes back mild: its F is a half step above E, so it carries one caution, the same as C major. By that measure it is no more remote than the parent scale.

But the B♭ in it is a half step below the major seventh, and no chord tone sits a half step above a B♭, so a rule that only looks upward never notices it at all. And B♭ is not a colour over this chord. It is the flat seventh. It says C7 — a different chord, a different function, a different place in the tune. It is the loudest disagreement in the table and the one measurement built on avoid notes is deaf to it.

That is why contradiction is measured separately, and why it is the thing that decides rank while the avoid note does not. Any player knows the difference by ear in an instant; the work is in saying it precisely enough that a piece of software knows it too.

Ionian or Lydian at the top

One question stays genuinely open, because the sources leave it open. Aebersold's ordering puts C Ionian first over Cmaj7, being the plainest reading of the written symbol. Russell's puts C Lydian first, being the more vertically unified parent. They agree on the tier and differ only on which of the two comes first inside it.

A player who has spent time inside the Lydian Chromatic Concept hears the second ordering as the natural one; a player raised on the Syllabus hears the first. Both are right about their own listening. The right shape for that is a single preference the player sets — a Lydian bias, on or off — rather than a second law arguing with the first, and rather than a silent choice made on their behalf.

Why this belongs in String Logic at all

String Logic builds music from intervals rather than from shapes, on any tuning, and it is designed to say why as often as it says what. A ranked list of scales over a chord is only worth as much as the reasoning underneath it — a list that cannot show its reasons is a list you have to take on faith, and taking theory on faith is the habit the app exists to undo.

So the reasoning is meant to be visible on the face of each row: how much of the chord this collection says, how many notes it brings from outside, how far it strays from the plain reading of the symbol, and whether one of its degrees wants handling with care. A player who disagrees with a placement can see exactly which measurement to argue with. That is the point.

This page describes work in progress rather than a finished surface, and it is published in that state on purpose — the reasoning should be arguable before it is built, not after.

Sources

The positions above are attributed to the writers who hold them. Where a text was consulted at second hand — through summaries, reviews and reference articles rather than the pages themselves — it is said so here, and nothing is quoted with a page number it does not have.

1. Jamey Aebersold, Scale Syllabus — the ordering principle and the major-family list. Read through the freely published introduction and corroborating chord-scale references; the printed order below the first two entries has not been checked against a physical copy. syllabus PDF
2. Barrie Nettles & Richard Graf, The Chord Scale Theory & Jazz Harmony (Advance Music) — the definition of the avoid note, quoted as it is reproduced across reference literature rather than from the book itself. publisher · summary
3. Mark Levine, The Jazz Theory Book — the passing-tone position, taken from reviews and reference summaries rather than the pages. review
4. George Russell, Lydian Chromatic Concept of Tonal Organization — the fifth-stacked parent scale and the ingoing/outgoing ladder. georgerussell.com · McClimon, SMT
5. Open Music Theory, “Chord-Scale Theory” — the standard pedagogical statement of the chord-scale relationship. chapter
6. Dmitri Tymoczko, scale networks and musical hierarchy — chord inside scale inside collection, with relatedness measured by shared tones and voice-leading distance rather than by penalties. Scale Networks and Debussy
7. David Temperley, key-profile models — the standard device for weighting a pitch class in a context instead of permitting or forbidding it. Consulted for the shape of the idea, not for its numbers.