Demonstrating “privileged frequencies” of a pipe

The resonance frequencies of an open pipe are harmonics of the fundamental frequency: f_n = nf₁. Each of these resonances can be excited by sound pulses occurring at the mth submultiple of the resonance frequency f_n/m = n/mf₁. These lead to a large number of “privileged frequencies” at which a woodwind reed or the brass player's lips can “lock in” to a wind instrument bore [A. H. Benade, Horns, Strings & Harmony (Doubleday, Garden City, NY, 1960), pp. 166–170]. Resonances and privileged frequencies of a 60‐cm pipe will be demonstrated with simple apparatus.