You are given two wind instruments of identical length. one is open at both ends, whereas the other is closed at one end. which is able to produce the lowest frequency?

1 Answer
Oct 3, 2014


The wind instrument with the closed end.


Excellent question.

Standing wave resonances in pipes have some interesting properties. If one end of the pile is closed, that end must have a "node" when sounding a resonance. If an end of a pipe is open, it must have an "anti-node."

In the case of a pipe closed at one end, the lowest frequency resonance happens when you have just this situation, a single node at the closed end and an anti-node at the other end. The wavelength of this sound is four times the length of the pipe. We call this a quarter-wave resonator.

In the case of a pipe opened at both ends, the lowest frequency resonance has one node in the center and anti-nodes at each end. This is a half-wave resonance; half of the wavelength is contained in the pipe. If this pipe is the same length as the closed pipe, the frequency of this resonance will be twice that of the closed pipe.