Also known as kettle drums. They have head widths ranging from 32" to 23", and each drum has a range of pitches to which it can be tuned by means of a foot pedal mechanism. They are usually played in groups of 4 or 5 of varying sizes so as to get a range of pitches. They produce low, full, rich sounds and are very enjoyable to play, because it involves movement of the entire body and can be very expressive, akin to the way one moves around a marimba while playing it. Tympani players often cross sticks or even their arms when playing complicated runs.
The mallets used for tympani are usally wooden sticks covered with a felt tip of varying thickness, which gives you a range of different qualities of sound. Sometimes straight wooden mallets, no felt, are used for a very loud, sharp, stacatto sound.
The pedals of tympani vary widely in quality and composition. Some rely entirely on friction to hold the head tension at a particular spot - these generally suck, because if you crank a head up to its highest pitch and then play repeated notes at forte or above, the thing is likely to loose its place, and the drum will go flat. Good pedals have a locking mechanism that is disengaged with the sideways motion of the foot, allowing you to move your foot up or down (down has increased the head tension, and thus the pitch, on every drum I've ever seen) to change pitch, and then re-lock the pedal.
The tuning of a tympani is a task unto itself. It requires a good ear, knowledge of how to produce a quite tone from the drum (so you are not heard doing this during a concert with an orchestra or percussion ensemble or what-have-you), and a small plethora of other things, some of which I will attempt to list here:
- Temperature will affect head tension and thus pitch. Even something like stage lights can produce enough heat to alter the pitch. Read: tune your drums less than ~5 minutes before your first piece, or you may find that their pitches have altered in that time.
- differentially tightened lugs - because tympani are lugged drums, their minimums and maximums of head tension, and thus pitch, are determined by the tightness of the lugs - and if even one of them is tighter or looser than the others, you won't get a true pitch out of the drum - it will sound "messy".
This can be corrected by tapping the head near each of the lugs with the butt of a mallet, slowly working your way around the head, going back and forth between lugs, listening for any pitch differences. If there are any, they can be negated by tightening or loosening the appropriate lugs.
- On the sides of the shells of timpani, on the side away from the pedal, there is usually some sort of screw mechanism that, when tightened, will slowly increase the head tension of all the lugs. This is useful for quick fixes when you suddenly realize that the upper range of your 23" is lower than the highest note you need to play - I've encountered 23"-ers that won't go above an E. Most will hit F#.
- If you happen to have the luxury of tuning in a quiet setting, you can use a neat trick to test whether a drum has reached the desired pitch, and you don't even have to get a tone out of the drum first: with your face no more than 6" from the head, hum the desired pitch at the drum and slowly change your pedal position. When the drum has reached this pitch, it will hum back at you - resonating in response to your hum. Be careful, though, you can sometimes get a false hum if you are humming a note that is a fifth above that to which the drum is tuned. It's not nearly as loud, though.
- If you are tuning during a concert, you have one of three options: 1. Strike the head gently with the butt end of the mallet, or press a fingernail into the head and flick your finger out: this will produce enough sound that you can tell what the pitch is at, without engaging the full resonate properties of the drum (i.e., without producing a lot of sound). While this tone is still sounding, adust the pitch. 2. You can use the tuning gage that might be on the side of your drum, 90 degrees from the pedal. 3. You can do it entirely by feel; a rather difficult task. This method is usually reserved for pitch changes that occur so quickly, even while playing on the drum, that you don't have time to use method 1 and your drum doesn't have a tuning gage. This takes a lot of practice.
- A device, which is basically a small harmonica of sorts, can be used to obtain pitches for tuning tympani. They are usually wheel-shaped, with 13 openings around the edge, each corrosponding to a different pitch. As the range of a standard set of tympani is F to F, these pitch pipes are manufactured with either an F to F range, or C to C (in other words, they encompass an entire octave, accidentals included).
- Alternately, an electronic tuner can be used. When a pitch is sounded near these things, they tell you where it is within something like a quarter of a whole tone.
For more information on actually playing tympani, check out tympani techniques