neirocca sound-first music theory

Analysis & Transposing

Form Viewer

See and hear the period, the sentence, binary and ternary form, the twelve-bar blues and AABA, with bar numbers, phrase boundaries and the cadence at the end of every phrase.

Form
Key

Two phrases that start with the same idea. The first stops on a half cadence, the second closes with an authentic cadence: question and answer. This is the commonest classical theme shape.

C Major · 8 bars

atools.formViewer.roles.questionbars 1–4
I1
IV2
ii3
V4

End of phrase: Half cadenceIt halts on the dominant, so you know more is coming.

a'tools.formViewer.roles.answerbars 5–8
I5
IV6
V7
I8

End of phrase: Authentic cadenceIt states its case and stops. This is a full stop.

The cadence shown is not a stored label. It is what the harmony engine returns for the last two chords of each phrase, so the structure holds up in any key.

Related Articles
Structure
8 barsa – a'
a: Half cadence · a': Authentic cadence

What is this tool?

Form is the plan of a piece: which units it is built from. Motives group into phrases, two phrases make a period, and periods group into binary and ternary forms. This tool lays out the standard shapes — period, sentence, binary, ternary, twelve-bar blues and AABA — with a roman numeral for every bar and clear phrase boundaries, and plays them. The cadence at the end of each phrase is worked out by the harmony engine from the last two chords, so the explanation still holds when you change key.

When it helps

  • Hear question and answer

    The first phrase of a period halts on a half cadence; the second closes. Playing them one at a time makes the difference between pausing and finishing unmistakable.

  • Use a form as a plan before you write

    Deciding on eight or thirty-two bars before writing the notes is the simplest way to avoid a piece that wanders. Borrow the harmonic skeleton and fill it in.

  • Check the standard blues and pop shapes

    The twelve-bar blues and AABA come with fixed listener expectations. Seeing them laid out shows where a song meets those expectations and where it breaks them.

How to use

  1. 1 Choose a form to see a roman numeral for each bar and the phrase boundaries
  2. 2 Play the whole form once to get a feel for where the breaks fall
  3. 3 Play one phrase at a time and compare how each one ends
  4. 4 Change the key and confirm that the structure is unchanged
  5. 5 Switch to another form and compare the bar counts and number of phrases

Related Tools

Lessons that use this tool

The sections of the systematic curriculum where this actually comes up.