Motion Maps

Chapter 17 — Part II, Motion: How Does the Bass Travel? Synthesis chapter: recombines this Part’s eight prior terms; introduces no new vocabulary.

The Question

Once you know all eight ways a bass line can travel, how do you read an entire phrase as a sequence of those choices?

The Mental Model

A Motion Map reduces a phrase to a labeled sequence of this Part’s own terms — Staying, Stepping, Approaching, Enclosing, Arpeggiating, Leaping, Connecting Chords, Contrary Motion. It introduces no new musical device of its own; it’s a representation, a way of reading a bass line that already exists (or one you’re about to compose) so every bar’s motion decision has a name.

That makes a Motion Map descriptive, not prescriptive. Mapping an eight-bar phrase after the fact is an analysis. Choosing each bar’s device before writing a single note is composition using the same vocabulary — both are valid uses of the same technique, but confusing them (treating a map as a fill-in-the-blanks formula rather than a naming exercise) misses the point of naming in the first place.

The real value of naming a bar’s device is that it makes the bar independently revisable. Without a name, “make bar 3 more interesting” is vague — interesting how, compared to what? With a name, the question sharpens: bar 3 is Arpeggiating, so the actual choices on the table are which chord tones, which order, which register, not an undifferentiated search through every possible note. This Part’s eight terms aren’t just labels for what already happened; they’re the menu you’re choosing from the next time you write a bar that doesn’t have one yet.

The Microscope

Four bars, four different motion decisions, each labeled as it happens.

Reading four decisions. Staying, Stepping, Arpeggiating, and Contrary Motion, one bar each.

Four bars moving from Cmaj7 through Dm7 to G7, each bar demonstrating one Part II term.

X:1
T:Motion Maps — reading four decisions
C:Alessandro Bessi
R:Concept study
M:4/4
L:1/8
Q:1/4=96
%%score { RH LH }
V:RH clef=treble name="Harmony"
V:LH clef=bass name="Bass"
K:C
[V:RH] "Cmaj7"[CEGB]8 | "Cmaj7"[CEGB]8 | "Dm7"[DFAC]8 | "G7"z2 c2 B2 A2 |]
[V:LH] "^stay"C,8 | "^step"C,2 D,2 E,2 D,2 | "^arpeggio"D,2 F,2 A,2 c2 | "^contrary"D,2 E,2 F,2 G,2 |]

Listen

Play Full and follow the annotation for each bar as it sounds. Then play Bass only alone and try to name each bar’s device purely by ear, before checking the label. The map should make what you already hear easier to describe, not teach you to hear something new.

See

Every annotation in this example names a term already defined earlier in this Part — nothing here is new. That’s the visual signature of a Motion Map: a phrase covered in familiar labels, none of them freshly coined for the occasion.

Play

Name the Route. Four bars, deliberately left unlabeled.

An unannotated four-bar bass line moving through Cmaj7, Am7, Dm7, and G7.

X:1
T:Name the Route
C:Alessandro Bessi
R:Exercise
M:4/4
L:1/8
Q:1/4=96
%%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"z6 [DFGB]2 |]
[V:LH] C,8 | A,2 B,2 c2 B,2 | D,2 F,2 A,2 c2 | z6 B,2 |]

Write your own one-word label above each bar before you play it: bar 1 holds still (Staying), bar 2 wanders by step around the Am7 root (Stepping), bar 3 outlines Dm7 directly (Arpeggiating), and bar 4 uses a single note to lean into the eventual return to C (Approaching). Play the line only after you’ve committed to your labels, then check whether playing it changes your answer.

Vary

Take “Name the Route” and change only bar 2’s contour from stepwise wandering to a single leap-and-recovery gesture. Relabel the bar. Notice that changing one bar’s device doesn’t require touching the map’s other three labels — that independence is what makes the map useful for revising a phrase one decision at a time.

The Music

“Complete the Map” is an original eight-bar fusion study in B major, in 7/8, that puts all eight Part II terms into one phrase, in the order this Part introduced them.

Complete the Map. Every term from this Part, once each, across eight bars.

An eight-bar fusion study in B major, in 7/8: Staying, Approaching, Stepping, Enclosing, Arpeggiating, Leaping, Connecting Chords, and Contrary Motion, in sequence.

X:1
T:Complete the Map
C:Alessandro Bessi
R:Fusion study
M:7/8
L:1/8
Q:1/8=200
%%score { RH LH }
V:RH clef=treble name="Harmony"
V:LH clef=bass name="Bass"
K:C
[V:RH] "Bmaj7"[B^d^f^a]7 | "Bmaj7"[B^d^f^a]7 | "G#m7"[B^d^f^g]7 | "G#m7"[B^d^f^g]7 |
"C#m7"[B^ce^g]7 | "C#m7"[B^ce^g]7 | "F#7"[^ce^f^a]7 | "F#7"z2 b2 ^a2 ^g1 |]
[V:LH] "^stay"B,7 | "^approach"B,5 G2 | "^step"^G2 ^A2 b2 ^A1 | "^enclose"^G3 D2 C2 |
"^arpeggio"^C2 E2 ^G2 b1 | "^leap"^C3 ^A2 ^G2 | "^connect"^F2 ^G2 ^A2 b1 | "^contrary"^C2 ^D2 E2 ^F1 |]

Reflection

“Complete the Map” uses each Part II term exactly once, in the order this Part introduced them. Write a motion map for an eight-bar bass line you already know from another piece of music — does it use all eight terms, favor a handful heavily, or reveal a device this Part never got to name?