Bass drum
A bass drum is a large, heavy drum that produces a "thump" of low but indefinite pitch. It is used in orchestral music, marching music, and throughout 20th century popular music as a component of the drum set.
In popular music, the bass drum is used to mark time. In marches it is used to keep the march even (marching bands march to the beat of the bass). A basic beat for rock and roll has the bass drum played on the first and third beats of a bar of common time, with the snare drum on the second and fourth beats, called "back beats". In jazz the bass drum plays less of a timekeeping role and serves more to punctuate the music. The same is true in classical music, though the styles are dramatically different.
An orchestral bass drum is quite large, about 36" in diameter, and is played with one or sometimes two large, padded mallets. Usually the right hand plays the drum and the left hand muffles it. When played with both mallets, a knee or forearm can be used for damping.
In a drum kit, the bass drum is much smaller, most commonly 20" or 22" but sizes from 18" to 24" are quite normal, 26" is not unusual in a big band, and extremes both larger and smaller are sometimes seen. It is usually more heavily muffled than the classical drum. It is played using a pedal operated mallet, which a right-handed drummer will conventionally operate with the right foot. A pedal-operated bass drum is often called a kick drum.
In some forms of jazz and many forms of heavy metal music, particularly thrash metal, power metal, and death metal, two bass drum pedals are used, one operated by each foot. Originally two identically tuned bass drums were used for this, but a double beater (twin-pedal) on the same drum using an extension mechanism (see illustration) is now more common. Some drummers have also experimented with two different bass drum tunings, sometimes combining this with double beaters so as to have more than two pedals.
With two feet playing bass drum, many of the techniques of snare drum playing (such as rudiments and rolls) can be performed on the bass. Double bass drum techniques were pioneered by Louie Bellson and Gene Krupa in the 1950s and popularised in the 1960s by Ginger Baker of Cream and Keith Moon of the Who. In certain types of metal, the drummer plays a constant stream of rapid-fire notes on the bass drum, and the ability to play evenly at extremely high tempos is prized. Some metal bands have turned to using triggers (which convert impacts into prerecorded or electronic drum sounds) or drum machines to attain high speeds, although this practice is generally frowned upon by fans.
In many modern marching bands and drum corps, a set of multiple bass drums called tonal bass drums are used. A bass drum line typically consists of four to six tonal bass drums, though many smaller high schools only have enough players to use two or three drums, and some universities and drum corps have marched up to sixteen at once. The drums typically are between 18" and 32" in diameter, but some groups have used bass drums as small as 14" and as large as 36". Generally, tonal bass drums are tuned higher than kick drums or orchestral bass drums so complex rudimental passages can be heard clearly. Each player usually carries one drum, though in rare cases players carry two or three smaller drums at once. Skilled bass drum lines can execute complex linear passages so convincingly that it sounds like the entire bass drum part is being played by a single musician.