Two open organ pipes of fundamental frequencies n1 and n2 are joined in series. The fundamental frequency of the new pipe so obtained will be :
n1 = V2L1 n2 = V2L2
Both open pipes joined
n=V2(L1+L2) = 12L1V+2L2V = 11n1+1n2=n1 n2 n1 + n2