As there are almost never less than two timpani in a symphonic orchestra, the instrument is usually spoken of in the plural, and the Italian name is universally adopted throughout the whole world.
The timpani can produce tones of definite pitch, which can be changed during the same work.
The Kettledrum is a copper basin of hemispherical shape, upon which a calf-skin (or any other substitute) is stretched. The basin usually rests on a tripod or any other variant.
The stretched membrane is held in place by a metal hoop which can be adjusted by tuning screws, evenly spaced and positioned around the hoop. By tightning the screws the membrane is stretched and its pitch heightened, and vice versa.
There are many types of timpani, but the most used are 23, 25, 28, and 30 inches in diameter.
It seems that the timpani came to us from the large drums, used in pairs and mounted on camels and horses. During the Ottoman Empire (about the 15th century) they were adopted by European cavalries and later began to be used in orchestras.
Screws were added in the 17th century, and Napoleon's musicians found that the Egyptian ketlledrums were tuned in the keynote and its dominant.
The timpanist usually constantly tunes his instruments during a concert, even while the whole orchestra plays, so that he has to have a very fine sense of pitch while almost inaudibly tuning. A special pedal helps the timpanist change the pitch while he plays. Of course the composer has to give him enough time to do so, by writing a number of rests in the score.
The use of pedals can produce tunes as well as a beautiful glissando.
The membrane has to be tensioned enough to produce a musical tone.
Timpani are almost always present in classical and romantic scores. When two instruments are used, they are usually tuned to tonic and dominant (the 1st and 5th notes of the chief key of the work).
The use of different sticks can produce a rich variety of tone qualities and shades of loudness. Most sticks have wooden handles, with heads made of flannel, wood, cork, sponge, and many more materials. The heads vary also in size.
The timpanist can mute the timpani by placing a piece of cloth on the head just opposite the striking point.
When a short note is asked for, the timpanist stops the vibration of the stretched membrane by the use of his fingertips. To play a sustained or long note, he uses a rapid alteration of single strokes.
Beethoven was on of the first composers to tune his timpani in octaves (in his 8th and 9th Symphonies). From the Romantic period onwards, composers called for more than two timpani in the orchestra, thus enlarging the number of percussionists needed. In his "Symphonie Fantastique" Berlioz calls for 4 players for 4 drums, and not less than 10 timpanists for 16(!) timpani in his famous "Requiem".
