In a closed organ pipe of length L, the fundamental frequency is f₁ = v/4L. The harmonics present are:
AAll harmonics (f₁, 2f₁, 3f₁, ...)
BOnly odd harmonics (f₁, 3f₁, 5f₁, ...)
COnly even harmonics (2f₁, 4f₁, 6f₁, ...)
DOnly the fundamental (no overtones)