The grouping together of instruments of various kinds to form an orchestra first came about in the early 1600’s. The first orchestras were haphazard collections of bowed and plucked strings and various types of wind instrument together with a keyboard instrument such as the harpsichord. Often, a composer would include whatever musicians were available to him at the time, and so the number of players and types of instruments would vary considerably from one composition to another.Late 17th to mid 18th centuryStrings mainly used, but flute, recorders, oboes, bassoon, perhaps horns and occasionally trumpets and kettledrums were used to accompaniment the strings. A constant feature used in this time was the harpsichord continuo – the player ‘continuing’ throughout the music to fill out the harmonies and to hold the ensemble together.Mid 19th centuryTowards the end of the 18th century, the woodwind section was invented. This included the flute, oboe, bassoon and the recently invented clarinet. While the harpsichord continuo fell out of use, a pair of kettle drums or a pair of trumpets was now often included. For some time, this formation of orchestra was accepted as standard, and is often called the ‘Classical orchestra’.Mid 19th centuryDuring this time the size and range of the orchestra increased. Trombones were now regularly used and the number of horns used was increased to four and the brass section was now complete with the addition of a tuba. This section now took on far greater importance as its range and flexibility was increased by the invention of the valve system. More woodwind instruments, such as the piccolo, cor anglauis, bass clarinet and double bassoon, – were now available and the choice of percussion instruments became more varied. The number of string players was necessarily increased in order to keep a balance of sound.Late 19th century to the present dayThe orchestra was vastly expanded at the beginning on the 19th century and now included extra brass and triple or even quadruple woodwind. Some composers began to write for much smaller orchestras in 1910; a small body of strings, one or two each of various kinds of woodwind and brass, and maybe one or two controlling a varied selection of percussion. In the 20th century composers have experimented with newly invented instruments discovering entirely new sounds and new techniques. Modern technology is also used.Key Words and TermsAccompaniment: A vocal or instrumental part that supports the primary part or provides background for a vocalist.Allegretto: Meaning moderately fast, slower than allegro.Anacrusis: The weak beat, with which the phrase may begin.Binary Form: A two-part song form consisting of an initial section, which is then followed by a contrasting section.Continuo: A bass line that repeats throughout an entire piece of music, or a section of the piece. Played by the lowest instrument, a continuo usually consists of a bass line and a series of figures.Diminished Seventh: A chord which contains the most fundamental note of a chord, often the bass note, a minor third, a diminished fifth and a diminished seventh.Disco: A type of dance music made popular in the discotheques of the 1970s, characterised by the relentless heavy accents on the strong beats.Dominant Key: The fifth scale tone above the tonic, or the triad built on that tone.Drone: A long held background note (similar to pedal) against which the tune is played.Falsetto: A high, artificial voice used to sing notes that are above the normal register.Funky: A type of music that bridges the gap between jazz and electronic pop. It is a musical structure defined by an electric bass style and a heavy back beat rhythm. Considered a down and dirty style of urban pop.Gavotte: A French musical term, meaning French dance.Harmony: The use of chords to provide an accompaniment to a melody. When pitches are in agreement.Hi-Hat Cymbals: A pair of cymbals mounted on a stand with a foot pedal. Depressing the pedal causes the cymbals to close creating a splash or a “chick” sound.We use the word style to describe the characteristic manner in which composers – of different times and of various countries- combine and present basic ingredients in their music.MELODY – Melody is the most important ingredient in a piece of music.’A series of notes of different pitch, organised and given shape to make musical sense to the listener’. This is basically the tune in a piece of music.HARMONY – Heard when two or more notes of different pitch are sounded at the same time, producing a chord. Chords are of two types: concords, in which the notes agree, and discords, in which the notes disagree. A harmony is lots of melodies.RHYTHM – Used to describe the ways in which a composer groups together musical sounds. In the background of a piece of music there will be a regular beat – the steady ‘beat’ or ‘pulse’ of the music, against which the ear measures rhythm. Rhythm is the beats in a piece of music.TIMBRE – describes the characteristic sound of an instrument. Timbre is the sound of the instruments.FORM – The word form is used to describe how a piece of music is built up, a basic plan or design which a composer may use to shape a piece of music.TEXTURE – Some pieces of music present a dense sound: rich and smoothly flowing where other pieces may have a thinner sound: sparser sound where the music produces a spiky/jagged effect. If there is a thick texture many instruments may be used, where as if there is a thinner texture only one or two instruments may be used.- Monophonic texture: a single melodic line entirely without supporting harmonies of any kind. One instrument.- Polyphonic texture: two or more melodic lines weaving along at the same time. Two or more instruments.- Homophonic texture: a single melody line heard against a chordal accompaniment. Sounds like a hymn.