For this the instrument must be longer and have additional keys which the player operates with the right thumb and/or little fingers (as with the basset horn).
[citation needed] The contra-alto clarinet has a curved bell, mainly made of metal, which is necessary for sound projection.
Unlike other low wind instruments (contrabassoon, tuba, ...) it can play a wide range of nuances from "fff" to "ppp" and articulations ("legato", "staccato", slap, ...).
[citation needed] In the mid-1960s, pieces in which contra-alto clarinets were also used were said to be heard even from the loudspeakers of small television sets.
[citation needed] The instrument was also in Hollywood: early episodes of The Twilight Zone, Star Trek [citation needed] Given the limited written repertoire in orchestras and ensembles, contra-alto clarinets can play in unison with other low wind instruments or provide a foundation in the lower octave to the woodwinds playing higher (organ pedal effect).
Recordings in which the contra-alto clarinettist appears as a soloist or chamber musician are extremely rare.