The Classical style: balanced phrases, Alberti bass and sonata form

Something changes around 1750 that a listener can hear in a single bar. Baroque music is woven; Classical music is spoken. Where Bach sets several equal lines running and lets them spin on, Haydn states a phrase, pauses, and answers it — and the pause is the point. Everything distinctive about the period follows from that shift, including its greatest invention, sonata form.

Texture: one thing at a time

The default Classical texture is homophony: a single melody over a subordinate accompaniment. Counterpoint does not disappear — Mozart’s finales and Haydn’s quartets are full of it — but it becomes a device deployed for effect rather than the medium itself.

The clearest symptom of this at the keyboard is the Alberti bass, named after Domenico Alberti: the left hand plays the notes of a chord in a repeating low-high-middle-high pattern while the right hand sings. A harpsichord or early piano cannot sustain, so breaking the chord keeps the harmony sounding without the accompaniment ever drawing attention to itself. Once you have heard it you will hear it everywhere in Mozart, and in the young Beethoven, and it is nearly a period stamp on its own.

Phrasing: music with punctuation

Baroque phrases spin forward by sequence until a cadence eventually arrives. Classical phrases are laid out in balanced units, most often four bars answered by four bars. The first, the antecedent, stops on a half cadence, unresolved, like a question. The second, the consequent, closes on a perfect cadence. Together they form a period.

This is why Classical music sounds like speech and why its tunes are so memorable: they come in sentences, with punctuation, and they end. That regularity is also what later composers had to break to sound modern, and what Haydn and Beethoven play games with.

Practically, this gives you a two-second test. Does the music have full stops? Does it ever simply halt, leaving silence, before resuming with something new? If yes, you are after 1750. If it runs on with no place you could conduct a breath, you are probably before it.

Sonata form, plainly

Sonata form is not a mould but a dramatic plot, and the plot is about key.

Exposition. The first theme (or first subject group) is stated in the home key. A transition modulates away. A second theme arrives in a new key — the dominant if the movement is in the major, usually the relative major if it is in the minor — and the section closes there. In the eighteenth century it is normally repeated whole.

Development. The themes are broken into fragments, recombined, sequenced, put through remote keys and generally destabilised. The characteristic feeling is of not knowing where you are, which matters because the resolution depends on that anxiety.

Recapitulation. Both themes return — but now the second theme is also in the home key. That is the entire payoff. The tension the exposition created by placing a good tune in the wrong key is discharged by bringing it home.

Coda. An optional tailpiece, brief in Haydn and Mozart, enormous in Beethoven.

The listener’s practical cue is not counting sections but noticing the moment where a familiar melody returns and this time stays put.

The orchestra grows up

The Classical orchestra standardises across the second half of the century. Strings remain the core, but the winds become permanent and independent: pairs of flutes, oboes, bassoons, horns, often trumpets and timpani, and — the dating detail worth remembering — clarinets, which join properly in the 1780s and 1790s. Mozart’s last symphonies and his clarinet concerto (1791) mark their arrival as full citizens.

Meanwhile the harpsichord vanishes. The continuo’s harmonic job is absorbed by sustaining winds and inner strings, so the orchestra holds itself up. No continuo plus clarinets is a very strong signal for 1780 or later. And because the orchestra can now control volume by degree, the gradual crescendo — a Mannheim speciality that became universal — replaces the Baroque’s terraced blocks.

Three composers on one page

Haydn (1732–1809) invented much of the style and spent forty years testing what it could withstand. His wit is structural, not decorative: false endings, sudden silences, movements that appear to stop and then do not, and the monothematic exposition, where the “second theme” turns out to be the first theme transplanted into the new key. The jokes only land because the convention is secure, which is a kind of confidence Mozart and Beethoven never quite share.

Mozart (1756–1791) thinks operatically even in instrumental music. His melodies breathe like a singer, with expressive leaning notes (appoggiaturas) that sigh into resolution, and with long-breathed phrases that nevertheless stay in proportion. His darkening is chromatic and local: a bar or two of shadow, then recovery. Where Haydn surprises, Mozart inflects.

Early Beethoven (c. 1795–1805) keeps the frame and assaults it from inside. Listen for sforzando accents landing on weak beats, sudden extremes of dynamic without transition, a bass line that is heavier and more rhythmically insistent, one small motif chewed over far longer than Haydn would allow, and codas so extended they amount to a second development. From about 1800 he replaces the courtly minuet with a fast, driven scherzo.

Late Haydn versus early Beethoven

This is the confusion the question-setters like, because the London symphonies (1791–95) and Beethoven’s First (1800) share an orchestra, a form and, for a while, a teacher.

A blunt rule: ask what the music does after the surprise. Haydn re-establishes balance almost at once. Beethoven uses the surprise as a reason to keep going.

The traps

Long careers crossing the line. Haydn’s early symphonies of the 1760s are pre-Classical in scale; his last quartets sit beside Beethoven’s Op. 18. Beethoven’s Op. 1 is Classical, his Op. 131 is not, and both are by the same hand.

Galant and Empfindsamkeit. The music of the 1740s to 1770s — J. C. Bach, C. P. E. Bach, the Mannheim school, Boccherini — is already homophonic, phrase-balanced and light, sometimes still with a continuo. Thin, tuneful, slightly formulaic music with a harpsichord underneath is probably this transitional repertoire, not mature Haydn.

Neoclassicism. Prokofiev’s Classical Symphony (1917), Stravinsky’s Pulcinella and Poulenc wear the manners of 1780 on purpose. The costume slips at the harmony: a chord that side-steps somewhere no eighteenth-century composer would go, or an orchestral colour that did not exist.

Schubert is not Mozart. Schubert (1797–1828) uses Classical forms but expands them lyrically, modulates by third rather than by fifth, and shifts between major and minor for colour rather than for drama. Long, repetitive, ravishing and harmonically sideways means Schubert.

How to spot it in ten seconds

1. Is there a continuo? A harpsichord chugging underneath sends you back to the Baroque; its absence is the first Classical clue.
2. Does the music have full stops? Balanced four-plus-four phrases with audible cadences and silences mean after 1750.
3. Melody or weave? One clear tune with subordinate accompaniment is Classical; several equal lines are Baroque.
4. Listen to the left hand. A broken-chord Alberti pattern under a singing line is almost a period signature.
5. How do dynamics change? Gradual swells point Classical or later; block loud-soft contrasts point Baroque.
6. Are clarinets present? Their presence in the orchestra pushes you to the 1780s or after.
7. Does a theme return and stay in the home key? That is the recapitulation, so the movement is in sonata form.
8. What is the third movement of four? A dancable minuet suggests Haydn or Mozart; a fast hard scherzo suggests Beethoven or later.
9. What happens after a surprise? Quick restoration of balance says Haydn; escalation and a huge coda say Beethoven.
10. Does the line sing like a singer? Vocal breath, sighing appoggiaturas and local chromatic shading point to Mozart.