Accoustic Resonance of an open tube -- help please So I am trying to make sense of the different varying formulas that I have found. Some of the formulas are not fully explained hence my questions. This is a music related topic. I am attempting to figure out what the formula is to determine the frequency of a stainless steel pipe (the one constant) with air pushed through it with these following variables. (A) Length of pipe (B) Wall thickness of pipe (C) CFM going through the pipe (D) Inner Diameter of pipe Also I have read that overblowing a pipe will cause the frequency of the note to jump an octave. At what point is it considered to be overblowing a pipe? Is there a formula for the max cfm prior to the said overblowing?