Related
Non-chord tones covered what they are (passing, neighbour, appoggiatura, suspension…). This entry covers how to treat them — the compositional level, and the place where writing skill shows.
Why is treatment harder than classification? Because a foreign note is by nature a dissonance. The dissonance is not the problem; the problem is that it must sound intentional. The same foreign note handled well is flavour, handled badly is an error — with identical pitches.
Four rules of treatment
| # | Rule | Reasoning |
|---|---|---|
| 1 | resolve by step | a foreign note should leave by step to a neighbouring chord tone; leaving by leap makes it sound like a chord tone |
| 2 | shorter than its neighbours | it is normally shorter than the chord tones either side; held long it *becomes* a chord tone |
| 3 | prefer weak beats | a foreign note on a strong beat needs explicit resolution and is more constrained (which is why appoggiaturas and suspensions are "licensed" strong-beat types, not free ones) |
| 4 | align with the harmonic rhythm | which chord it falls on is a choice — and that choice decides whether it is decoration or reinterpretation |
The fourth is the most overlooked and the most useful:
The same note landing on a different chord is a different thing entirely. A D over a C chord may be a passing note; the identical D on the far side of a barline over a G chord is a chord tone. So the first step in treating a foreign note is not "how do I write this note" but "which chord does it fall on".
A common treatment error
Putting foreign notes in the bass. The bass is the most attended-to register (see chord voicing), so a foreign note there instantly becomes a protruding dissonance that sounds like a wrong note.
For the same reason, a foreign note should not form a strong clash with the bass (a minor second or a tritone). In traditional writing the bass is almost always a chord tone — and that is why. The exception is the suspension: a suspended bass is one of the most forceful closing devices (see pedal point and the suspension resolutions in cadence).
Two fates for one foreign note
| Treatment | Result |
|---|---|
| foreign note → step → chord tone (short, weak beat) | heard as decoration; the phrase flows |
| foreign note held, left by leap, or in the bass | heard as an error, even with identical pitches |
Diagram: one note, two identities
Listen: how placement changes everything
Use the progression player and watch where each chord lands. The same melodic note is decoration over one chord and a chord tone over the next — so the first step in judging a foreign note is not hearing the note but hearing which harmony it lands on.
Common misconceptions
- "Treating foreign notes is a check you run afterwards." It is the first decision while writing: settle
- "Fewer foreign notes is safer." The opposite: they free a melody from the chord (see
- "If it resolves, it is correct." Duration and voice position matter too. A foreign note in the bass still
- "The rules are classical dogma." Modern music treats foreign notes far more freely, but the goal — making a
which chord the note falls on, then decide how to write it.
non-chord tones). The issue is treatment, not avoidance.
sounds like a collision even when it resolves.
dissonance sound intentional — has not changed, and neither has the test. :::
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 外音处理惯例（级进解决、短时值、弱拍优先、与和声节奏配合）为和声学与对位学通则
- 强拍外音须明确解决、且以倚音与延留音为主要类型，为通行表述
Used for fact-checking only; all prose is original.