Odd harmonics in a closed tube

The closed tube has only odd harmonics: $n = 1, 3, 5, ...$

Figure 4: Standing waves for pressure in an closed tube

For odd $n$, the harmonics of the closed tube have the following properties:

• wavelength: $${\lambda = \frac{4}{n}L_n}$$.
• frequency: $${f_n = n\frac{v}{4L}}$$.