The contra-alto clarinet, E♭ contrabass clarinet, is a large clarinet pitched a perfect fifth below the B♭ bass clarinet. It is a transposing instrument in E♭ sounding an octave and a major sixth below its written pitch, between the bass clarinet and the B♭ contrabass clarinet. The contra-alto clarinet is often used in clarinet choirs and ensembles of clarinets and saxophones. It may also be present in a wind band. The repertoire for contra-alto clarinet in the symphony orchestra is limited. In ensembles it is usually used in unison with the other woodwind instruments, such as (bassoon, bass clarinet and contrabass clarinet), or it plays the lower octave in addition. History The contra-alto clarinet is largely a development of the 2nd half of the 20th century, although there were some precursors in the 19th century: In 1829, , an instrument maker in Göttingen, introduced an instrument tuned in F in the shape and fingering of a basset horn, which could be called a contrabasset horn because it played an octave lower than it. Around 1890 the Belgian clarinet maker Eugène Albert or his son E. J. Albert also developed an alto clarinet in F, but without the additional basset notes typical of the basset horn notated C to it. In 1851, Adolphe Sax applied for a patent<ref>Description des machines et procédés spécifiés dans les brevets d'invention, publ. par C.P. Molard. [With] Table générale des vingt premiers volumes. [Continued as] Description des machines ... pour lesquels des brevets d'invention ont été pris sous le régime de la loi du 5 juillet 1844 Ministère de l'agriculture et du commerce, Description des machines et procédés spécifiés dans les brevets d'invention pour lesquels des brevets d'invention ont été pris sous le régime de la loi du 5. juillet 1844 (Description of the machines and processes specified in the patents for which patents have been taken out under the law of 5 July 1844).</ref> for an instrument, he called "contrabass clarinet in E♭" in order to replace the bowed contrabass of symphony orchestras in wind bands with an instrument whose lowest sounding note is contra-G or G1, like the contrabass. This is the case with a contra clarinet tuned in E♭, whose written lowest tone is the small E♭ (E-flat3), as with most clarinets. The pitch of this instrument today identifies it as a contra alto clarinet. However, it never came onto the market. Around