1) "Western instruments are also often classified by their musical range in comparison with other instruments in the same family. These terms are named after singing voice classifications: Soprano instruments: flute, clarinet, recorder, violin, trumpet Alto instruments: oboe, alto flute, viola, horn Tenor instruments: English horn, trombone Bass instruments: bassoon, double bass, bass clarinet, tuba Some instruments fall into more than one category: for example, the cello may be considered either tenor or bass, depending on how its music fits into the ensemble, and the trombone may be alto, tenor, or bass and the French horn, bass, baritone, tenor, or alto, depending on which range it is played. Many instruments have their range as part of their name: soprano saxophone, alto saxophone, tenor saxophone, baritone saxophone, baritone horn, alto flute, bass flute, alto recorder, bass guitar, etc. Additional adjectives describe instruments above the soprano range or below the bass, for example: sopranino saxophone, contrabass clarinet. When used in the name of an instrument, these terms are relative, describing the instrument's range in comparison to other instruments of its family and not in comparison to the human voice range or instruments of other families. For example, a bass flute's range is from C3 to F♯6, while a bass clarinet plays about one octave lower." Source and further information: http://en.wikipedia.org/wiki/Musical_instrument_classification#Instruments_by_range 2) "While some woodwind instruments have no theoretical upper limit to their range (although they often have practical limits), they generally cannot go below their designated range. This is not the case for brass instruments. All brass instruments can play beyond their designated ranges. Notes lower than the brass instrument's designated range are called pedal tones; notes higher than the designated range are called screech notes. The playing range of a brass instrument depends on both the technical limitations of the instrument and the skill of the player. While woodwind and brass instruments can play above (and in the case of brass instruments below) their designated ranges, it is not often called upon in classical arrangements. It is extremely rare for musicians to play the extremes of their instruments. The most common exception is that of trombones. Bass trombones are occasionally asked to play pedal tones." 3) The instrument with the smallest range could be the triangle: "When ignoring pitch modulation and damping, the triangle appears to require no specialist ability to play and is often used in jokes and one liners as an archetypal instrument that even an idiot can play. The Martin Short sketch comedy character Ed Grimley is the best known example. However, triangle parts in classical music can be very demanding, and James Blades in the Grove Dictionary of Music and Musicians writes that "the triangle is by no means a simple instrument to play". In the hands of an expert it can be a surprisingly subtle and expressive instrument. Most difficulties in playing the triangle come from the complex rhythms which are sometimes written for it, although it can also be quite difficult to control the level of volume. Very quiet notes can be obtained by using a much lighter beater — knitting needles are sometimes used for the quietest notes. Composers sometimes call for a wooden beater to be used instead of a metal one, which gives a rather "duller" and quieter tone."