i found a website that describes a four-note flute made from a bear's thigh
bone found in a cave in northern yugoslavia in 1995, believed to be the
oldest known musical instrument at over 43,000 yrs old and pre-dating
one-note whistles 20-30,000 yrs old. it sure is hard to believe there
weren't drums, rattles, rythmn sticks as well.
here's the site with other links at the bottom: