Tong Keat has an M.A. in Violin Performance from MTSU, TN. He is the founder of Just Violin—a free resources site for violinists.
The string instruments found in an orchestra can be categorized into two groups—bowed string and plucked string.
The bowed string instruments, also known as the violin family, consist of the violin, viola, cello, and double bass. These instruments have four strings and are played with a bow.
Sounds are produced by drawing the horsehair of the bow across the strings, creating vibrations that would be amplified by the wooden body of the instrument. The bowed string instruments can also be played by plucking on the strings with the fingers (pizzicato) or tapping the strings with the wooden part of the bow (a performance direction known as col legno).
The most common plucked string instrument found in an orchestra is the harp. Some people may consider the harp as a standalone instrument, not belonging to the orchestral string family. The harp is a beautiful instrument capable of playing glissando and arpeggio passages very effectively.
The harp has seven pedals that are used to change the notes chromatically so that it can play in any key. The guitar, banjo, and mandolin are also plucked string instruments, but they are rarely seen in an orchestra.
The four main woodwind instruments found in an orchestra include the flute, clarinet, oboe, and bassoon. Some orchestra music, especially music from the Romantic and 20th-century periods, tend to have a more elaborate woodwind section that uses instruments such as piccolo, alto flute, cor anglais, bass clarinet, double bassoon, and saxophone.
The flute (includes piccolo and alto flute) is held horizontally and played by blowing through a mouth hole. The flute and piccolo can often be seen playing rapid passages in the orchestra. The clarinet is a transposing instrument—in which the written pitch is different from the actual sounding pitch.
The most commonly used clarinets are the clarinet in B flat and A. In general, the clarinets are capable of playing with a wide range of dynamics. The saxophone family includes the soprano, alto, tenor, baritone, and bass saxophones. They are used occasionally in some of the modern orchestral pieces. The clarinet and saxophone are single-reed instruments of the woodwind family.
The oboe’s sound is very projecting, and it plays the concert A for the orchestra to tune to before the start of an orchestra concert or rehearsal. The cor anglais, also known as the English horn, is quite similar to the oboe. It produces a much deeper and warmer tone than the oboe.
The bassoon is a low-sounding woodwind instrument. The bassoon and double bassoon (also known as contrabassoon) usually play the bass part of the music, and they are very effective in playing articulated passages. The oboe, cor anglais, bassoon, and double bassoon are double reed instruments of the woodwind family.
The four main brass instruments include the horn, trumpet, trombone, and tuba. The horn is a transposing instrument, and the horn in F, in particular, is known as the French horn. The sound of the horn blends in nicely with the woodwind instruments, and therefore, it is used in a woodwind quintet.
The trumpet is the highest sounding instrument of the brass family, commonly featured in loud and rhythmic orchestral tutti passages. Like the horn, the trumpet is also a transposing instrument. The cornet looked like a trumpet and was favored mainly by French composers in the early romantic period.
The trombone is the only brass instrument that uses a slide instead of valves. The slide has seven positions, and that allows it to play in every key. The trombone is not a transposing instrument, and its parts are written in the bass clef.
The tuba is the largest and lowest sounding instrument of the brass family. It is also a non-transposing instrument. The euphonium looks like a smaller tuba, and it is a brass instrument rarely seen in an orchestra but more prominent in a symphonic band or wind ensemble.
The percussion family covers a wide range of instruments, and they can be divided into two categories—definite pitch and indefinite pitch. Percussion instruments that give a clear pitch include timpani, xylophone, tubular bells, and glockenspiel. The timpani are always used in pairs or more, with each timpani pre-set to a specific pitch. Also known as the kettledrum, the timpani is a very prominent percussion instrument in the orchestra. It is often used to make drum rolls and to enhance the rhythmic effect of the music. Notes on the xylophone (wooden bars), tubular bells (metal tubes), and glockenspiel (metal bars) are arranged like a piano keyboard and played by hitting them with mallets.
Instruments of indefinite pitch are used primarily for rhythmic purposes, and their music scores are usually notated on a single line. The more commonly seen instruments in the orchestra include the bass drum, snare drum, cymbals, gong, triangle, and tambourine.
© 2017 Goh Tong Keat
Louise Powles from Norfolk, England on November 02, 2017:
I'd love to be able to play the harp. That sounds so beautiful.