Duduk maestro Manvel Mnatsakanyan explains in this video the different types of duduks, their qualities and sounds, and even gives a introductory lesson on how to play the duduk. This video is great introduction to the great diversity of the duduk and the many different sounds the instrument can make. I think my favorite was the duduk in D--it has a bright sound that isn't typical of the duduk, which is often described as the saddest instrument in the world.
Armenian musicologists cite evidence of the duduk's use as early as 1200 BC, though Western scholars suggest it is 1,500 years old. Variants of the duduk can be found in Armenia and the Caucasus. The history of the Armenian duduk music is dated to the reign of the Armenian king Tigran the Great, who reigned from 95–55 B.C. According to ethnomusicologist Dr. Jonathan McCollum, the instrument is depicted in numerous Armenian manuscripts of the Middle Ages, and is "actually the only truly Armenian instrument that's survived through history, and as such is a symbol of Armenian national identity ... The most important quality of the duduk is its ability to express the language dialectic and mood of the Armenian language, which is often the most challenging quality to a duduk player."
For anyone who is interested, Manvel actually conducts duduk lessons with students from around the world via Skype!