Vacuum cleaner tube

This astuteness was given to us but we haven't been able to use it yet: Completely dismantle your vacuum cleaner to collect the draft tube. This tube must be rather long. Unite index and middle fingers (for once, the left-handed are invited to the rejoicings!) and strike an end of the tube with the bone making the junction between the last phalanxes.

What do you hear ? Miracle ! A tabla ! And you're not in India !