<P> That said, the score does allow the interpreter to make choices on how to perform a historical work . For example, if the tempo is written with an Italian instruction (e.g., Allegro), it is not known exactly how fast the piece should be played . As well, in the Baroque era, many works that were designed for basso continuo accompaniment do not specify which instruments should play the accompaniment or exactly how the chordal instrument (harpsichord, lute, etc .) should play the chords, which are not notated in the part (only a figured bass symbol in the bass part is used to guide the chord - playing performer). The performer and the conductor have a range of options for musical expression and interpretation of a scored piece, including the phrasing of melodies, the time taken during fermatas (held notes) or pauses, and the use (or choice not to use) of effects such as vibrato or glissando (these effects are possible on various stringed, brass and woodwind instruments and with the human voice). </P> <P> Although Classical music in the 2000s has lost most of its tradition for musical improvisation, from the Baroque era to the Romantic era, there are examples of performers who could improvise in the style of their era . In the Baroque era, organ performers would improvise preludes, keyboard performers playing harpsichord would improvise chords from the figured bass symbols beneath the bass notes of the basso continuo part and both vocal and instrumental performers would improvise musical ornaments . Johann Sebastian Bach was particularly noted for his complex improvisations . During the Classical era, the composer - performer Mozart was noted for his ability to improvise melodies in different styles . During the Classical era, some virtuoso soloists would improvise the cadenza sections of a concerto . During the Romantic era, Beethoven would improvise at the piano . For more information, see Improvisation . </P> <P> The instruments currently used in most classical music were largely invented before the mid-19th century (often much earlier) and codified in the 18th and 19th centuries . They consist of the instruments found in an orchestra or in a concert band, together with several other solo instruments (such as the piano, harpsichord, and organ). The symphony orchestra is the most widely known medium for classical music and includes members of the string, woodwind, brass, and percussion families of instruments . The concert band consists of members of the woodwind, brass, and percussion families . It generally has a larger variety and number of woodwind and brass instruments than the orchestra but does not have a string section . However, many concert bands use a double bass . The vocal practices changed over the classical period, from the single line monophonic Gregorian chant done by monks in the Medieval period to the complex, polyphonic choral works of the Renaissance and subsequent periods, which used multiple independent vocal melodies at the same time . </P> <P> Many of the instruments used to perform medieval music still exist, but in different forms . Medieval instruments included the flute, the recorder and plucked string instruments like the lute . As well, early versions of the organ, fiddle (or vielle), and trombone (called the sackbut) existed . Medieval instruments in Europe had most commonly been used singly, often self accompanied with a drone note, or occasionally in parts . From at least as early as the 13th century through the 15th century there was a division of instruments into haut (loud, shrill, outdoor instruments) and bas (quieter, more intimate instruments). During the earlier medieval period, the vocal music from the liturgical genre, predominantly Gregorian chant, was monophonic, using a single, unaccompanied vocal melody line . Polyphonic vocal genres, which used multiple independent vocal melodies, began to develop during the high medieval era, becoming prevalent by the later 13th and early 14th century . </P>

What kind of music would most likely be performed by a symphony orchestra