Arpeggiating

Chapter 13 — Part II, Motion: How Does the Bass Travel?

The Question

What turns a series of leaps into something that sounds intentional rather than random?

The Mental Model

Arpeggiating means outlining two or more tones of the current chord in a directed melodic sequence — the bass tracing the harmony’s own structure rather than borrowing a shape from outside it.

A single leap isn’t yet an arpeggio. Leaping (Chapter 14) covers the general device of a large interval used for emphasis, whether or not it lands on a chord tone or continues anywhere afterward. The moment a leap keeps going — continuing on to state a second and third chord tone in sequence — it becomes something more specific: an Arpeggiating gesture that outlines the chord itself.

A leap sounds random unless something explains where it’s going next; an arpeggio supplies that explanation by continuing along a known, finite set of notes — the chord itself. Once a listener recognizes the second note as also belonging to the same chord, every subsequent leap becomes predictable in kind, even if its exact size varies, because the underlying rule (stay inside this chord’s stacked thirds) has already been established. That’s a different kind of coherence than Stepping’s — Stepping is smooth because each note is close to the last one; Arpeggiating is coherent because each note belongs to the same small, named set, no matter how far apart the notes actually sit in register.

The Microscope

Both versions start with the same leap from C. Only whether it continues changes what the gesture is.

A — A single leap. C jumps to A, a color tone, and stops.

One bar: a root leaping up a sixth to the 13th, with nothing following it.

X:1
T:Arpeggiating — a single leap
C:Alessandro Bessi
R:Concept study
M:4/4
L:1/8
Q:1/4=92
%%score { RH LH }
V:RH clef=treble name="Harmony"
V:LH clef=bass name="Bass"
K:C
[V:RH] "Cmaj7"[CEGB]8 |]
[V:LH] "^leap"C,4 A,4 |]

Listen

Play Bass only on both. A’s leap to A is a single, isolated color choice — it doesn’t explain itself any further. B’s continuation makes the harmonic logic audible: every note names a specific chord tone, in order, so the ear can follow the chord’s own shape rather than just registering one jump.

See

B’s four notes — C, E, G, B — are exactly Cmaj7’s stacked thirds, read straight off the chord symbol above. That’s the visual test for Arpeggiating: can you name each bass note as a specific numbered chord tone in sequence? If the notes don’t map onto the current chord’s own structure, the line is doing something else — Stepping, Leaping, or Connecting Chords instead.

Play

Outline the Chord. A full ascending arpeggio under each of four different chords.

Four bars, each bass line tracing its own chord's root, third, fifth, and seventh.

X:1
T:Outline the Chord
C:Alessandro Bessi
R:Exercise
M:4/4
L:1/8
Q:1/4=92
%%score { RH LH }
V:RH clef=treble name="Harmony"
V:LH clef=bass name="Bass"
K:C
[V:RH] "Cmaj7"[CEGB]8 | "Am7"[ACEG]8 | "Dm7"[DFAC]8 | "G7"[DFGB]8 |]
[V:LH] "^arpeggio"C,2 E,2 G,2 B,2 | "^arpeggio"A,2 C2 E2 G2 | "^arpeggio"D,2 F,2 A,2 C2 | "^arpeggio"G,2 B,2 D2 F2 |]

Before playing each bar, say the four chord-tone numbers out loud — “root, third, fifth, seventh” — then play them. If you can’t name a note’s number without stopping, you’re not yet arpeggiating that chord; you’re guessing at a shape.

Vary

Play the same four arpeggios in a different order (root, fifth, third, seventh, for instance) instead of strict ascending thirds. Does the line still read as an outline of the chord, or does breaking the ascending order make it start to sound like something else?

The Music

“Full Outline” is an original eight-bar jazz study in Ab major, swung throughout, built entirely from ascending and descending arpeggios, one full outline per chord.

Full Outline. Every bar traces its chord fully, alternating ascending and descending direction.

A swung eight-bar jazz study in Ab major outlining Abmaj7, Fm7, Bbm7, and Eb7 in turn.

X:1
T:Full Outline
C:Alessandro Bessi
R:Jazz study
M:4/4
L:1/8
Q:1/4=100
%%score { RH LH }
V:RH clef=treble name="Harmony"
V:LH clef=bass name="Bass"
K:C
[V:RH] "Abmaj7"[_ac'_e'g']8 | "Abmaj7"[_ac'_e'g']8 | "Fm7"[f_ac'_e']8 | "Fm7"[f_ac'_e']8 |
"Bbm7"[_b_d'f'_a']8 | "Bbm7"[_b_d'f'_a']8 | "Eb7"[_eg_b_d']8 | "Eb7"[_eg_b_d']8 |]
[V:LH] "^arpeggio"_A,2 C2 _E>G | "^arpeggio"_A2 G2 _E>C | "^arpeggio"F2 _A2 c>_e | "^arpeggio"_e2 c2 _A>F |
"^arpeggio"_B,2 _D2 F>_A | "^arpeggio"_A2 F2 _D>_B, | "^arpeggio"_E2 G2 _B>_d | "^arpeggio: settle"_E8 |]

Reflection

“Full Outline” never leaves its current chord to arpeggiate — every note in a given bar belongs to that bar’s own harmony. What would change about the piece’s character if one bar’s arpeggio borrowed a tone from the next chord instead?