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A soprano clarinet is a clarinet that occupies a higher position, both in pitch and in popularity, than subsequent additions to the family such as the basset horn and bass clarinet. The B♭ clarinet is by far the most common type of clarinet and the unmodified word clarinet usually refers to this instrument. However, due to a tendency for writers and historians to imitate the terms used to denote instruments in other instrumental 'family groups' the term soprano is sometimes used to apply not only to the B♭ clarinet but also to the clarinets in A and C, sounding respectively a semitone lower and a whole tone higher than the B♭ instrument, and even the low G clarinet—rare in Western music but popular in the folk music of Turkey—sounding a whole tone lower than the A. While some writers reserve a separate category of sopranino clarinets for the E♭ and D clarinets, those are more usually regarded as soprano clarinets as well. All have a written range from the E below middle C to about the C three octaves above middle C, with the sounding pitches determined by the particular instrument's transposition.
The only instrument of the clarinet family whose name is undisputed and always required is that of the bass clarinet. The use of the terms soprano, piccolo, and sopranino is, at best, relatively rare and of debatable accuracy. These terms came about specifically to distinguish the 'clarinet' from its lower-pitched, younger siblings and have been applied later and only in that context. Even the term alto (for the E♭ instrument a fifth below the B♭ 'soprano') is open to discussion and the alternative term tenor might appear, from the point of view of pitch at least, to be more appropriate.
Orchestral composers largely write for clarinets in B♭ and A. The bass is not uncommon and the high E♭ is very occasionally called for, often referred to simply as E♭ clarinet. Clarinets in C were used likewise from the Classical era until about 1910. Wolfgang Amadeus Mozart also called for clarinets in B♮ when writing in very sharp keys (e.g. the E major arias in Idomeneo and Così fan tutte), but this became obsolete far sooner. There have also been soprano clarinets in C, A, and B♭ with curved barrels and bells marketed under the names Saxonette, Claribel, and Clariphon.
Shackleton lists also obsolete "sopranino" clarinets in (high) G, F, and E, and soprano clarinets in B♮ and A♭. The G (sopranino) clarinet, only a half step lower than the A♭ piccolo clarinet, was popular during the late 19th century in Vienna for playing Schrammelmusik. B♭ soprano clarinet is also one of the most common instruments played in beginner and high school band, alongside the bass clarinet.