Back in 1999, Chinese archaeologists in collaboration with Garman Harbottle, a scientist at Brookhaven National Laboratory on Long Island, unearthed what is believed to be the oldest known playable musical instrument – in the form of a 9,000-year old seven-holed flute. The 9-inch long object in question was crafted by shaping the hollow wing bone of a large bird, and was found in a pretty well preserved state (along with six other flutes) at Jiahu, an archaeological site in Henan Province of China. Interestingly enough, Jiahu is also probably home to the earliest example of human-worked silk, as suggested by findings inside a tomb at the site.
Coming back to this millennia old flute, harking back to early Neolithic period in China, there are extant marks to suggest that the flute was tuned. According to a New York Times article (published in 1999) –
Nine millennia after lips last touched it, the flute was played again and its tones analyzed. The seven holes produced a rough scale covering a modern octave, beginning close to the second A above middle C. There is evidence that the flute was tuned: a small hole drilled next to the seventh hole had the effect of raising that hole’s tone from roughly G-sharp to A, completing the octave.
The article also goes on to mention –
It is impossible to know what relationship, if any, the tones have to six- or seven-tone Chinese scales first documented 6,000 years later (the other intact flutes have five to eight holes, but are not playable because of their condition). But the fact that the playable flute had a carefully selected tone scale indicates that the Neolithic musicians may have been able to play more than single notes, but actual music.
Now since this subject entails the history of music, historians have already reconstructed the music of the world’s oldest known song, ironically discovered in northern Syria – one of the focal points of a modern-day military conflict. Known as the Hurrian Song to Nikkal, you can listen to the recreated version here. And in case you are interested in Classical artistic accomplishments, researchers have also reconstructed ancient Greek music with the world’s oldest known ‘complete’ song.

Image Source: National History Magazine
Via: OpenCulture
It was the oldest at the time of its discovery (1989, not 1999 and not in collaboration with Garman Harbottle) until maybe 2008. The audio above was recorded in 1989.
This article, written May 25th, 2012, describes the discovery of instruments found in cave in Southern Germany which have been carbon dated to somewhere between 42,000, and 43,000 years old.
While this is, no doubt, an old instrument, it is by no means “The World’s Oldest Known Playable Musical Instrument”.
Source: http://www.bbc.com/news/science-environment-18196349
Fascinating
A better structure for that sentence from the Post would have been;
not only to play single notes, but actual music.