The bassoon's double reed gives it a rich, slightly buzzing quality in the lowest notes and a sweet nasal sound higher up. Bassoons can be extremely expressive as solo instruments and their warm vibrato enables them to sound remarkably human, a little like a resonant baritone singer. They are also great for creating punchy rhythmic lines and as bass instruments they help provide support for the whole orchestra.
Because of their versatility, bassoons have been used in orchestras for a very long time. There are a variety of larger and smaller bassoons, but these days the most commonly used additional member of the bassoon family is the contrabassoon which sounds an octave lower than the bassoon.