A close relative of the bassoon, it might be considered a bass bassoon as such. In the same fashion as other instruments with the prefix "contra", the sounding pitch is an octave below the written pitch. This is to say that a written A of 440Hertz would, when played on a contrabassoon actually be 220Hz.
Many fellow musicians have been surprised to learn that note fingerings for the contrabasson are not directly equivalent to bassoon fingerings. Indeed, in a particular range, the note series is one fifth different between equivalent fingerings.