Extending and Continuing

Continuation rarely fails at the first note; it fails where the form has to decide what comes next.

Related

Thematic TransformationSonata FormTempo

The problem

Continuing looks like the easy job: hand over an existing audio file or MIDI part and ask for more. Failure seldom happens on the first note. It starts around bar eight, where the motif circles, the section has no destination, the place that should change keeps repeating, and the ending stops abruptly. Listeners cannot name the fault, they just feel it is no longer the same piece. It shows most in instrumental cues, where no lyric holds the structure up.

How it works

The only condition a continuation model gets is the passage before it. It is good at carrying surface features, tempo, key, timbre, texture density, but it will not decide the form for you. So the destination belongs in the conditions: total length, whether to modulate, which bar changes section, how to close. Key and meter are the floor; a suggested next transformation of the motif is worth more than a pile of adjectives.

Practice

Cut eight to sixteen bars as the start, ideally ending on an open phrase, since a continuation after a cadence usually just adds another cadence. Put tempo, key and meter into the prompt or the session, and realign after generating. Ask for two versions, one that merely continues and one that develops, by variation or modulation, and compare which sounds like the same piece. Then rewrite the last two bars so the close lands where your form needs it, and let the joined passage stand alone before extending again.

What to listen for

In a tune like The Unfinished, which exists only as a first half, whether the added melody stays in the same mode or quietly changes scale. In Handel's chaconne, whether the ground bass survives the continuation. In Bach's chromatic fantasia and fugue, how the texture changes after the fantasia without changing the language. In Reger's introduction, passacaglia and fugue, how one idea carries a long span.

Sources

• 续写与接续的常见失败点，依生成工具公开文档核对，未抄原文
• 曲式与动机发展的判断方法，依作曲教学通识核对，未抄文本

Used for fact-checking only; all prose is original.