The true musical answer is - all of the ones included in a single musical piece -
Musicians have argued this for many a long year. But all agree if a piece is written for all the instrument in the orchestra and one fails to play then it is noticeable. therefore every instrument that the composer wrote the piece for is vital.
Chat with our AI personalities
For the brass section: trumpets, trombones, horns (French) and tubas.
For the string section: violins, violas, cellos, and bass viols.
For the woodwind section: flutes, oboes, clarinets, and bassoons.
For the percussion section: timpani, drums, xyplophone/marimba/glockenspiel, and piano if necessary.
Also instruments such as harps which I can't remember how to classify :P.
It is all according to which part of the orchestra the music was written for. If it was a Fanfare then it would be the brass section. As has already been explained in other answers to a similar question, every instrument has its own part to play to complete the whole of the piece. You cannot have a sweet lullaby without the string section and perhaps the harp. Each has its own part to play in any given piece of music. Listen carefully to any orchestrational piece and will be able to pick out all of the sections.
Instruments payed in Orchestra are,
Celesta
Piano
Harp
Violins
Violas
Violoncellos
Double basses
Piccolo
Flutes
Oboes
English Horn
Clarinet
Bass Clarinet
Bassoons
Contra bassoon
Saxophone
Horns
Trumpets
Trombones
Tuba
Timpani
Snare Drum
Tenor Drum
Bass Drum
Cymbals
Tuned gongs
Tam-tam
Triangle
Wood block
Tambourine
Glockenspiel
Xylophone
Vibraphone
Chimes
Castanets
Congas
Bongos
Whip
There are string instruments, wind instruments, brass instruments and percussion section in a concert orchestra. Until the late classical period, the string section played an important role. Since after, every section has equal importance.
The right answer is Mandolin
Piccolo, though some percussion instruments can be smaller.
The piano and the violin were the most popular solo instruments used in the concerto of classical period. The violin was one of the most popular for the baroque period, and the increase in popularity of the piano caused that this instrument replaced the former. See http://au.encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761553032
In a string orchestra, the instrument with the lowest pitch is the Bass (also called Double Bass, String Bass, Upright Bass, and Contrabass)
The London Symphony Orchestra