Today's Blogging A-to-Z challenge post will take a look at common musical forms.
We've already seen some examples of common musical forms, even though I didn't call them out: the canon and the fugue. Both are imitative forms, though as you've seen the fugue is far more complex than the canon. "Row Row Row Your Boat" is a canon (but, of course, someone made a fugue out of it).
When we talk about other forms, we usually note large sections of music with letters. So a form of, say, A-B-A means that you have a theme first, then another theme, and then the first theme comes back.
The basic musical forms all show up in symphonies written between about 1760 and 1830, in the Classical and Early Romantic periods. Haydn codified the symphonic template, Mozart perfected it, and Beethoven took it up a notch.
The first movement of a Classical symphony usually uses sonata allegro form. It starts with an optional introduction, progresses to exposition, through development, then a recapitulation, and concludes with an optional coda. In short, A-B-A1, because the recapitulation usually doesn't strictly repeat the exposition.
The first movement of Mozart's Symphony #25 demonstrates this beautifully. The exposition starts immediately, stating the bold g-minor theme in several forms for the first 90 seconds or so. Development ensues, taking us around several related keys and themes (including the primary theme). The recap begins at 5:05, once he's brought it back to g minor. Note, also, that Mozart wrote this at 17.
Second and fourth movements often use rondo form, which is A-B-A, A-B-A-C-A, or A-B-A-C-A-B-A. The A just keeps coming around, you see. Here's Haydn's 49th symphony, second movement. It deviates from a typical classical symphony in that the second movement is fast, not slow as was common in the period. But it's a complete A-B-A1-C-A2 rondo, as well as an excellent example of the Sturm und Drang ("storm and stress") period in the late 1770s-early 1780s.
Third movements generally follow the minuet and trio form, which uses 3/4 time and a simple A-B-A or A-B-C-A form. Example: Brahms' Symphony #3, third movement. Even though Brahms wrote this decades after Mozart and Haydn had died, it still maintains the minuet and trio form—though with lusher orchestration and harmonies than either classical composer would have used.
Listen for these forms the next time you hear a symphony. They're in there.