Week 15 · Chapter

Week 15 — Chapter · Charts, Keys, and the Real World

Music Theory I · MUS 156 Fictional sample

Course: MUS 156 Music Theory I · Kenosis College
Instructor: Professor Hemsworth
Unit: Learning Unit 15 of 16 (Week 15) · two sessions per week
The unit's primary reading · ~30–40 minutes · SLOs 8, 4, and 5 · Read this before the first session if you can — everything else in the module builds on it, and this unit closes a day early.

You already hear this

Welcome back. The break is behind you, the final is a week and change ahead, and between them sits the unit the other fourteen were building toward. Nothing in this chapter is brand new. Every tool here — intervals, keys, chord symbols, Roman numerals — you already own. What's new is the room they get used in: a soundcheck, a rehearsal, a napkin chart, a trumpet player looking at you expectantly.

Here is the whole unit in one scene. Saturday morning, your band is running the opener. The vocalist stops mid-chorus: "It's sitting too high — can we take it down?" At the same soundcheck, a friend shows up with a trumpet and asks what key you're in — and her answer is not your answer, because her instrument tells a beautiful, consistent lie. Meanwhile the bandleader is scribbling 1 5 6m 4 on the back of a set list, and everyone but you seems to know what it means.

Fifteen weeks ago, that scene was three separate panics. By the end of the week it's three short errands. You already hear everything involved — you've been moving songs to friendlier keys by ear since before you could name a key. This week, the arithmetic catches up with the reflex, and you leave with the working musician's three superpowers: transpose anything, read and realize any chart, and talk harmony in the numbers every bandstand understands.

Where we are

Behind you: addresses and steps (units 1–3), all thirty keys and the circle (4–5), interval arithmetic (6–7), the midterm that certified it, chords and their symbols (9–10), Roman numerals and function (11), cadences (12), and two units of writing real lines (13–14). Ahead of you: only the final — and its whole review family (study guide, prep tutorial, practice exam) has been open since week 14. This unit deliberately introduces nothing the final will test cold. It's a synthesis unit: old tools, real jobs. That includes The Chart, your term project, which comes due with this unit — more on that at the end.

Transposition: moving the house without breaking the dishes

Sing the first phrase of Amazing Grace. Now sing it again, starting somewhere lower. You just transposed — no paper, no fear. Notice what survived the move: every step, every leap, the lean toward home, home itself. Transposition moves music to a new pitch level while keeping every relationship intact. The addresses change; the song — which lives entirely in the relationships between addresses — doesn't.

On paper, transposition is interval arithmetic applied to everything at once. Choose the interval, choose the direction, and move every note and every chord by exactly that much, spelled properly. Here is a four-bar phrase in F major, with its chords — F, B♭, C7, F:

KEY: F major    METER: 4/4    CLEF: treble
| F4/q G4/q A4/h | Bb4/h D5/h | C5/q Bb4/q G4/q E4/q | F4/w |

In plain English: the melody steps up F4–G4 to a held A4, moves to B♭4 and leaps up to D5, then walks down through the notes of C7 — C5, B♭4, G4, E4 — and settles on a whole-note F4. Chords underneath: F for a bar, B♭ for a bar, C7 for a bar, F to close. (In numbers you'll meet later this chapter: 1, 4, 5, 1.)

Say the singer wants it a minor third lower. Then every note goes down a m3, and unit 6 does the rest: F4 → D4 · G4 → E4 · A4 → F♯4 · B♭4 → G4 · D5 → B4 · C5 → A4 · E4 → C♯4. The chords make the identical trip: F → D, B♭ → G, C7 → A7. The result:

KEY: D major    METER: 4/4    CLEF: treble
| D4/q E4/q F#4/h | G4/h B4/h | A4/q G4/q E4/q C#4/q | D4/w |

In plain English: the same phrase a minor third lower, now in D major — D4–E4 to a held F♯4, G4 leaping up to B4, walking down through A7's notes (A4, G4, E4, C♯4), landing on D4. Play them back to back: your ear files them as the same song.

Two ways to run the same errand. You can transpose by interval — move each note down a m3 and let the new key reveal itself — or by key: decide up front that F major becomes D major, swap the key signature (one flat out, two sharps in), and rewrite each note at the same scale degree it occupied before. ^1 stays ^1; ^5 stays ^5. Both roads give one answer; fluent musicians use one and check with the other.

Misconception check. "Transposing changes the song." It changes the addresses. Every interval, every function, every cadence — the entire pattern your ear knows as "the song" — survives untouched. That's not an accident; it's the definition. If something musical broke, you didn't transpose; you made a mistake.

The singer says it's too high

The most common transposition request in the real world arrives in exactly those words. It has a one-word answer with an interval attached, and the word is worth the whole unit:

Too high → transpose DOWN. Too low → transpose UP.

Obvious in print — and routinely inverted in the field, because under pressure "change the key" gets tangled with "make it brighter," and up feels like doing something generous. Run the numbers instead. This unit's studio song peaks at E5. Suppose your singer's comfortable ceiling is C♯5. The gap from E5 down to C♯5 is a minor third — so the whole chart moves down a m3, and the new peak lands exactly on her best note. If you moved up a m3 instead, the peak would arrive at G5 — you'd have made the problem worse by precisely the amount you "helped."

The full procedure, once: find the melody's peak → learn the singer's ceiling → measure the gap → move everything down by that interval. (Too low? Same procedure upside-down, with the melody's floor.) Notice this is a kindness you can only perform with the tools: your ear hears "too high"; units 6–7 measure how much; this unit moves the house.

Misconception check. "Up a minor third fixes a too-high song." Peak-note test: peak E5, up a m3 → G5. Worse. The fix for too high is down — check it with a peak note every single time, and you will never invert it under pressure.

Transposing instruments: written is not sounding

Hand your trumpet-playing friend a melody in C and ask her to play it. She plays every written note flawlessly — and what comes out of the bell is a major second lower than your piano. Nobody made a mistake. A B♭ trumpet is built so that its written C sounds B♭. That's what "a B♭ instrument" means.

The rule that organizes the whole family: written C sounds the instrument's name.

B♭ instruments (trumpet, clarinet): written C sounds B♭ — a major second lower than written. (Tenor sax is also a B♭ instrument but adds an octave: it sounds a major ninth below written. The interval class you transpose by is the same M2; the copyist adds the octave.)
E♭ instruments (alto sax): written C sounds E♭ — a major sixth lower. (Bari sax adds an octave below that.)
F instruments (horn, English horn): written C sounds F — a perfect fifth lower.

Since the instrument sounds lower than its page, the copyist writes higher than the target sound. To make a transposing player produce concert pitch, write B♭ parts a M2 above concert, E♭ parts a M6 above, F parts a P5 above.

Worked example, all three at once. The band needs to hear concert C4. The trumpet part shows D4 (a major second up). The alto part shows A4 (a major sixth up). The horn part shows G4 (a perfect fifth up). Three different pages; one pitch in the air. And it scales straight up to keys: if the band is in concert G major, the trumpet reads in A major (up a M2), the alto in E major (up a M6), the horn in D major (up a P5). Here's the trumpet case on the staff — first what the room hears, then what her part shows:

KEY: C major    METER: 4/4    CLEF: treble
| C5/h D5/h | E5/w |

The concert line — what everyone hears: C5 and D5 as half notes, then a whole-note E5.

KEY: D major    METER: 4/4    CLEF: treble
| D5/h E5/h | F#5/w |

The trumpet part — the same line written a major second higher (D5, E5, F♯5), so that what sounds is the concert line above. Written up, because the instrument sounds down.

Why would anyone build instruments this way? So one set of fingerings serves a whole family. A saxophonist who learns one system can pick up alto, tenor, or bari and read fluently on each — the pages absorb the differences so the fingers don't have to. The cost is a fixed, known disagreement between page and air, and the person who absorbs that cost is whoever writes the parts. This week, that's you.

Misconception check. "B♭ instruments play wrong notes." The trumpet plays exactly what's written; the page was pre-moved so the sound comes out right. Keep two words glued to every pitch this week — written vs. sounding (or concert) — and every sentence you say about transposing instruments will be true.

The lead sheet: a kit, not a shortage

A lead sheet is a song reduced to what the band can't improvise: the melody, the chord symbols above it, and maybe the lyric. No piano arrangement, no bass line, no drum groove. That's not music missing; that's music trusting you. Every player realizes the symbols — turns them into an actual part — according to their instrument and role:

Keys / guitar: build the chord from unit 10's symbol grammar — Cmaj7 is C–E–G–B tonight and every night — and voice it where it doesn't collide with the melody or each other.
Bass: play roots — and honor every slash, because the letter after the slash is the bass note the arranger actually wants: G/B means the chord is G major and your note is B.
Everyone: the melody rules. Symbols serve the tune, not the reverse.

Reading a lead sheet is the exam your last six units already passed: symbols (10), function (11), cadences (12), and the good judgment about lines you built in 13–14. The only new skill is trusting yourself to fill the deliberate blanks.

Nashville numbers: Roman numerals in street clothes

In unit 11 you learned to store progressions as numbers, not letters — I–V–vi–IV — precisely so they'd survive a key change. Nashville's session musicians industrialized the same idea with Arabic numerals: the Nashville Number System writes each chord as its scale degree in the song's key, with minor chords marked m (some charts use a minus sign: 6−).

Here is a loop in G major — the chords G, Em, C, D:

KEY: G major    METER: 4/4    CLEF: treble
| <G3,B3,D4>/w | <E3,G3,B3>/w | <C4,E4,G4>/w | <D4,F#4,A4>/w |

In plain English: four whole-note chords — G major (G–B–D), E minor (E–G–B), C major (C–E–G), D major (D–F♯–A). On a Nashville chart, that whole line is just: 1 · 6m · 4 · 5.

Now the trick that pays the rent. The singer wants it in E? The letters all change — E, C♯m, A, B — but the numbers don't move: still 1 · 6m · 4 · 5, because C♯m is still the 6-chord of its key. One napkin, every key. That's why the numbers exist.

And say the equivalence plainly, because it's this week's biggest "wait — I already know this": Nashville numbers are Roman numerals in street clothes. 1 = I, 4 = IV, 5 = V, 6m = vi, 2m = ii. Arabic instead of Roman, an m doing the work of lower case. Not a different theory — the same theory, dressed for work. (The chord on 7 is diminished and rare on charts; when it appears, it's marked.)

Misconception check. "The numbers are always counted from C." They're counted from the song's key — 1 is wherever home is. In G, the 4-chord is C; in E, the 4-chord is A. It's movable do for chords, and you've been singing movable do since unit 4.

The roadmap: how a one-page chart plays a four-minute song

Charts stay short by refusing to write anything twice. The navigation marks — the roadmap — are a tiny Italian vocabulary plus two symbols:

Repeat signs — play the enclosed section again (once more, unless a count says otherwise).
First and second endings — first time through, play ending 1; on the repeat, skip ending 1 and play ending 2.
D.C. (da capo, "from the head") — go back to the top of the chart.
D.S. (dal segno, "from the sign") — go back to the sign (𝄋), wherever it was planted.
al Fine — after the jump, play until the word Fine and stop there.
al Coda — after the jump, play until the "To Coda" mark, then leap to the Coda (𝄌), the chart's tail section.

So D.S. al Coda reads: back to the sign, play until "To Coda," jump to the Coda, end there. Before the downbeat, trace the itinerary with a finger and say it out loud — professionals literally do this ("top, repeat, D.S. at the bridge, coda after the last chorus"). Thirty seconds of tracing prevents the classic train wreck.

Misconception check. "D.C. and D.S. are interchangeable." D.C. returns to the top; D.S. returns to the sign. The sign exists because "the top" isn't always where the music should go back to. Confuse them and half the band is in the verse while the other half plays the bridge — a sound you only need to hear once.

Sidebar: when the arithmetic hands you an unplayable key

Transpose a song in F♯ major down a minor third and the math says the new tonic is D♯ — landing you in "D♯ major," a key that would need nine sharps and doesn't exist among the fifteen. The working move: respell enharmonically and write the chart in E♭ major (three flats), which names the same sounds on readable paper. Two honesty rules from unit 1 still apply: D♯ and E♭ are the same sound and different spellings, and you say out loud that you respelled — you performed a service to the reader, not a shrug. (This judgment call is exactly why the course kept insisting enharmonic means "sounds alike," never "equals": today it saves a horn section.)

Why this makes you a better musician

This unit skips the sales pitch, because this unit is the product. When the singer says it's too high, you move the entire chart down a minor third during a water break — peak note checked against her ceiling — instead of negotiating with physics all afternoon. When the trumpet kid joins the worship team, you hand him a part written a major second up, in the right key, and he plays it correctly the first time; he never knows how close he came to an unplayable afternoon, which is exactly how competence feels from the outside. When the bandleader calls "one–five–six minor–four in B♭," you're comping before the sentence ends. And when someone asks why the bridge hits the way it does, you can answer in real words — function, cadence, the deceptive swerve — because that's the other half of this unit's project: The Chart, due at this week's close, where you do all of the above to a song you chose because you love it. Fifteen weeks ago you could hear all of this. Now you can say it, write it, and hand it to somebody — which is the whole difference between having an ear and being the musician the band relies on.

Key terms

Transposition — moving music to a new pitch level while keeping every interval and relationship intact; done by interval (move each note) or by key (swap signature, keep scale degrees).
Concert pitch — the actual sounding pitch, as a piano or voice would name it.
Written vs. sounding pitch — what a transposing player reads vs. what comes out; they differ by the instrument's fixed interval.
Transposing instrument — an instrument whose written C sounds another pitch: B♭ instruments sound a M2 lower than written; E♭ instruments a M6 lower; F instruments a P5 lower. Parts are therefore written that interval above concert.
Lead sheet — a chart carrying melody, chord symbols, and (maybe) lyric; each player realizes their own part from it.
Chord-symbol realization — turning a symbol (Am7, G/B) into actual notes for your instrument and role.
Nashville Number System — chords written as Arabic scale-degree numbers of the song's key (1 4 5, minors marked 6m or 6−); Roman numerals in street clothes.
Repeat signs / first and second endings — play the section again; take ending 1 first time, ending 2 on the repeat.
D.C. / D.S. — go back to the top (da capo) / go back to the sign (dal segno).
Fine / Coda — the marked stopping point / the chart's tail section, reached by "To Coda."

Summary

Transposition moves every note and chord by one interval in one direction — or equivalently, rewrites the same scale degrees in a new key. The addresses change; the song doesn't.
Too high → down. Too low → up. Measure the exact interval with the peak-note (or floor-note) test. Never invert the direction.
Transposing instruments sound lower than written — B♭ by a M2, E♭ by a M6, F by a P5 — so their parts are written that interval above concert pitch, and their key signatures move the same way (concert G major: trumpet A, alto E, horn D).
A lead sheet is melody + symbols; every player realizes a part from it. The slash still names the bass note.
Nashville numbers are Roman numerals in Arabic dress — 1 = I, 6m = vi — counted from the song's key, which is why one chart survives every key change.
The roadmap: repeats, first/second endings, D.C. (top) vs. D.S. (sign), al Fine (stop at Fine), al Coda (jump to the tail). Trace the route aloud before you play.
When transposition lands in an unspellable key (F♯ down a m3 → "D♯ major"), respell enharmonically (E♭ major) and say so — same sound, readable spelling.

Check your understanding

Work these before peeking — they're ungraded, and worked answers follow at the bottom of the page.

Your singer says the bridge is too high — her ceiling is B4, and the bridge peaks at D5. Direction and interval, and what's the new peak?
The band is in concert E♭ major. Name the written key for the trumpet, the alto sax, and the horn.
A horn part shows written C5. What concert pitch does the room hear?
The key is D major. Spell the chords a Nashville chart means by 1 · 4 · 5 · 6m.
A chart's last line reads D.S. al Coda. Describe your exact route from that instruction to the final chord.

Answers (worked reasoning — read after attempting)

Down a minor third. D5 down to B4 is a m3 (D→B is three letter names D–C–B and three half steps). Move everything down a m3 and the new peak is exactly B4 — her best note, not a squeak. (Moving up a m3 would park the peak at F5: worse by exactly the amount moved.)
Written keys sit above concert because the instruments sound below: trumpet (B♭, up a M2) reads F major; alto (E♭, up a M6) reads C major; horn (F, up a P5) reads B♭ major.
F instruments sound a perfect fifth lower than written: written C5 sounds F4.
In D major: 1 = D (D–F♯–A), 4 = G (G–B–D), 5 = A (A–C♯–E), 6m = Bm (B–D–F♯). Numbers count from the song's key — never from C by default.
Jump back to the sign (𝄋 — not the top; that would be D.C.), play forward until the "To Coda" mark, then leap to the Coda and play it to the end. Trace it with a finger before the downbeat and say the route out loud.

Next in this module: the Readings & Resources page if you want other angles (including a lead-sheet grammar and a Nashville deep dive), then Tutorial 15 — due before Week 15's second session, because the studio transposes at full speed and assumes its reps. And The Chart is due with everything else the end of Week 15 — a day early this week, so the weekend belongs to the final.

~ Professor Hemsworth's edition · Kenosis College · built with thecoursemaker.com