What is a Clarinet in A?

A clarinet in A is a type of transposing clarinet that sounds a minor third lower than the written pitch. When a player reads and performs a written C on this instrument, the sounding pitch is A.

The A clarinet is commonly used in orchestral music, especially in pieces written in keys that would be difficult to play on the B♭ clarinet. Because of its transposition, it allows clarinetists to perform passages with simpler fingerings and fewer accidentals in certain keys.

Although similar in design and sound to the B♭ clarinet, the A clarinet is slightly longer and produces a tone that many musicians describe as slightly darker and warmer. Composers such as Mozart, Brahms, and Mahler frequently wrote parts specifically for the A clarinet in orchestral works.