Passing tones are unaccented non-harmonic tones that connect two harmonic tones stepwise and occur between chord changes. Unlike suspensions, they resolve upward or downward and create no strong dissonance. Identifying passing tones requires tracking scalar motion overlaid on harmonic change and distinguishing ornamental from structural pitches.
From your study of non-harmonic tones, you know the basic taxonomy: passing tones, neighbor tones, suspensions, anticipations, escape tones, and more. The passing tone is the most ubiquitous of these. Its defining feature is motion: it appears between two harmonic tones a third apart, filling in the gap with a stepwise connection. Think of the melody moving from E down to C (two harmonic tones a third apart) with a D in between — that D is a passing tone. It is not part of the chord, but it is not a mistake; it is a deliberate bridging note that makes the melodic line feel smooth and continuous rather than skipping.
The key to identifying a passing tone by ear is tracking two streams simultaneously: what the harmony is doing and what the melody is doing. The harmony provides the reference grid — the chord tones are the structural pitches, the ones that belong. When a melody note doesn't belong to the current chord but fits neatly in the stepwise flow between two notes that do, you are almost certainly hearing a passing tone. The word "passing" is apt: the note passes through on its way somewhere, landing neither long enough nor emphatically enough to claim harmonic status. It appears between the beats (unaccented) and moves on.
Contrast this with a suspension, which is the other common non-harmonic tone beginners confuse passing tones with. A suspension occurs *on* a strong beat — it is accented, not passing. It clashes against the new chord, holds briefly, and then resolves by step. The suspension commands attention; the passing tone quietly fills space. When you hear a dissonance that occurs exactly on the beat coinciding with a chord change, that is a suspension. When you hear a fleeting dissonance between beats, smoothly connecting two chord tones in a scalar line, that is a passing tone. The rhythmic position is the diagnostic key.
From your melodic dictation work, you have experience transcribing stepwise motion by ear. Bring that skill to bear on passing tone identification: when writing down a melody, notice which notes you can account for with the current chord and which you cannot. The unaccountable notes that appear between beats and fit in a scalar line are your passing tones. Chromatic passing tones follow the same logic but fill in half-step gaps that occur outside the scale — hearing a note that is "between" two diatonic pitches in a smooth scalar descent is the signature of a chromatic passing tone.
Building fluency with passing tones by ear requires practicing two-level listening: chord-tone identification at the bottom and melodic ornament recognition above it. Start with simple examples where passing tones are rhythmically obvious — an eighth note between two quarter notes on chord tones. Then move to faster contexts where passing tones appear as sixteenth notes in running figures. The underlying skill is learning to hear two simultaneous layers: the harmonic skeleton and the melodic surface that decorates it.
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