Percussion is the other major family of symphonic band instruments. They are called percussion instruments because most of them need to be struck to produce sound. They can be struck with the hands, drumsticks or pedals, however there are percussion instruments that produce sound by being shaken, scraped, pinched or rubbed. The percussion instruments family can be divided into two large groups: idiophones and membraphones. Idiophones are instruments that produce sound with their own body that vibrates without being subjected to any tension. In membraphones, the sound is produced by a membrane or skin that has to be stretched, that is, subjected to tension. Both idiophones and membraphones include instruments that can produce sounds with definite pitches and instruments that produce sounds with indefinite pitches; in the case of the latter, thanks to the advance of technology, it is now possible to manufacture models of certain instruments that can produce definite pitches, although they are rarely used for melodic purposes.
IDIOPHONES
XYLOPHONE
The xylophone consists a set of wooden bars (commonly known as blades) with different sizes. They are arranged horizontally, from the largest to smallest one (from the lowest-pitched to the highest-pitched sounds), from left to right. When struck with drumsticks, the blades vibrate producing sounds with definite pitches, which is why the xylophone is classified as a definite-pitch idiophone. The xylophone is very popular among the school population in its version for the so-called 'orff method'.
MARIMBA
The marimba can be used as a bass xylophone, as it is similar in every way; it is larger than the bass xylophone, and its bars (or blades) are longer and wider, allowing it to produce lower-pitched sounds. The marimba is usually built in such a way as to be at least one octave lower than the xylophone.
VIBRAPHONE
The vibraphone is also a definite-pitch idiophone. Similar to the previous ones, it has bars or blades, but they are made of metal. Underneath each vibraphone bar there are tubes that act as sounding boards that amplify the sound. These tubes have rotating discs that can be shifted by an electric motor that, when activated, covers and uncovers them consecutively, causing a sound ripple effect.
BLOCKS
Blocks are indefinite-pitch idiophones. They consist of small hollow boxes with different sizes open on one side. They are usually made of wood, but orchestras often have also PVC models. However, there are two different types of blocks: temple blocks and woodblocks. We usually keep the Anglo-Saxon terminology because what distinguishes them is not exactly their construction material. Despite their name, they can both be made of the materials mentioned above. Usually, temple blocks have a more rounded shape, allowing the sounding board to reflect the sounds that are produced for longer periods of time. Woodblocks are built essentially to highlight an attack. For example, the instrument we usually call a 'Chinese box' is woodblock.
CASTANETS
Castanets consist of a pair of hollowed out shell-shaped wooden pieces tied to the end of a short wooden stick that, when shaken, allows the pieces to strike against each other producing indefinite-pitch sounds. It is therefore an indefinite-pitch idiophone. In light music, we usually see castanets without a wooden stick, that is, tied only by a string and stricken directly with the hands.
VIBRASLAP
The vibraslap is an indefinite-pitch idiophone. This instrument consists of a wooden base to which a small, slightly oblique metal rod with a wooden sphere at the end is attached. The vibraslap produces sound when the sphere, stricken with the hand, is set in motion causing the metallic rod and, consequently, several small metallic cylinders to vibrate and strike the sounding board.
SLIT GONG
The slit gong is a larger gong. Gongs are a kind of larger, thicker and heavier cymbals built with an irregular surface that allows for a more diverse range of harmonics. They are suspended from a structure and produce sound by being struck with a drumstick of proportional size.
CYMBALS
Cymbals are metal discs that are either held in place by a leather handle attached to a hole in the centre of the cymbal, or suspended from a metal stand (usually a tripod). They produce sound by banging against each other, or by being struck with various types of drumsticks, so there are two types of cymbals: clash cymbals and suspended cymbals. They are also indefinite-pitch idiophones.
MEMBRANOPHONES
TIMPANI
Timpani consist of a stretched membrane or skin that covers a copper or fibreglass box, with a more or less hemispherical shape that can have various sizes. They are arranged in a semi-circle, in front of the percussionist - the largest and lowest-pitched on the left, and the smallest and highest-pitched on the right - who hits them with various types of drumsticks. A symphonic band can use several timpani, usually two to five, depending on the repertoire. Timpani can be tuned by stretching the membrane more or less, by means of screws or, in most models, with a pedal. The pedal allows producing the glissando effect. Thus, timpani are classified as definite-pitch membraphones.
BRASS DRUM
The brass drum has two large stretched membranes which are struck with a specific drumstick, generally known as a mallet. It is cylindrical and rests on a support that allows it to be placed in any position. It is an indefinite-pitch membraphone.
TOM DRUM
The tom drum has a stretched skin that is struck with two drumsticks. It is cylindrical, rests on a tripod, and comes in various sizes, which is why it is commonly referred to in the plural: tom drums. It is also an indefinite-pitch membraphone.
ELECTROPHONES
SYNTHESISER
A synthesiser is an instrument that produces sound by means of electronic oscillators or digital circuits. These electronic components in this instrument function like a taut string in a chordophone, or a column of air in an aerophone. The synthesiser is classified as an electrophone because the sound is generated by electronic means. Usually, the synthesiser is equipped with a keyboard which allows activating the different musical notes. The synthesiser's keyboard is organised just like those in acoustic key instruments, that is, by scrolling the keyboard from left to right, you ascend from the lowest-pitched to the highest-pitched sounds. The synthesiser, in addition to being able to generate different 'pitches' (different musical notes), is an instrument that has the ability to produce different timbres. One of the main benefits of this instrument lies precisely in the timbre, since it allows the creating new 'sounds' that cannot be produced by acoustic instruments. However, in addition to creating new timbres, the synthesiser also simulates the timbre of other instruments, although it cannot reproduce them exactly. An example of this is the fact that the synthesiser is regularly used to replace the pipe organ in churches or auditoriums where this instrument does not exist, which is why it is commonly known as 'electronic organ'.
DIGITAL PIANO
It is a musical instrument designed to simulate the sounds of keyboard instruments, mainly the piano. This is an electronic instrument that produces sounds by means of data stored digitally in a memory. Although it is an electronic piano, the designation 'digital piano' is more commonly used to distinguish it from early electronic pianos, which were analogue, not digital. It should not be confused with an electric piano, and even less with keyboard piano.