Percussion

Timpani are drums that play real pitches: a set of four covers roughly D2 to A3, and a pedal retunes each drum while the music goes on.

Struck, shaken or scraped

Percussion instruments make their sound when they are struck, shaken or scraped. That covers a very large group, so orchestras split it in two. Pitched percussion plays definite notes: timpani, xylophone, glockenspiel, tubular bells and others. Unpitched percussion makes sounds without a clear note: the snare drum, the bass drum, cymbals, the triangle, the tambourine and the tam-tam. The percussion section sits at the back on the highest riser, partly so that loud sounds do not cover the other players and partly because the instruments take up a lot of floor.

Timpani: the drums that sing notes

A timpano is a large copper bowl with a skin or plastic head stretched over the top. The air in the bowl and the tension of the head give it a clear pitch. A pedal tightens or loosens the head, so the player can change the note quickly. Most orchestras use a set of four drums of different sizes. According to the orchestralibrary.com range table, the largest common drum (about 32 inches) covers about D2 to A2 and the smallest standard one (about 23 inches) about D3 to A3. Timpanists tune by ear during rests, often humming quietly or tapping the head very softly.

In Classical music the timpani usually played two notes: the keynote and the fifth above or below it. In D major those are D and A, and that is what the timpani play in the model when you press Add a line three times. Because these two notes are the roots of the two main chords of the key, I and V, the drums add weight to the cadences. Beethoven gave the timpani more freedom; in the scherzo of his Ninth the drums are tuned an octave apart and burst in on their own.

The famous surprise

One player, many instruments

A percussionist often moves between several instruments in one piece: a stroke on the bass drum, then a roll on the snare, then a crash of the cymbals. The parts are planned so that one player has time to walk between them, and the instruments are laid out like a workshop. In the model three stations stand side by side for that reason. The bass drum gives a low thud with no clear pitch, the snare drum has wires stretched under the bottom head that rattle, and orchestral cymbals are clashed together in pairs or hung from a stand and struck.