Most instruments overblow at two times the speed of the fundamental frequency ( the octave ) but as the clarinet acts as a closed pipe system, the reed cannot vibrate at twice the original speed because it would be creating a'puff'of air at the time the previous'puff'is returning as a rarefaction.
12.
In the case where one end of an otherwise closed pipe is narrower than the other, the film at the narrow end will be a subset of the film at the wide end ( that is, they will be caps from spheres of the same radius ) .-- talk ) 14 : 57, 8 September 2010 ( UTC)
