Resonant frequencies of a musical wind instrument

Abstract

Listen

Translate article

We consider four possible ways of defining and calculating resonant frequencies of a closed‐open air column in a musical wind instrument: (1) maxima of an input impedance versus frequency curve, (2) maxima of a power input curve, (3) frequencies at which input reactance vanishes (i.e., zero phase angle, where input impedance is purely resistive), and (4) frequencies at which a pressure antinode occurs at the inlet. For many bore shapes (cylinder, trombone bell, etc.) these yield nearly the same frequencies. However there are others such as a simple truncated cone for which these methods give results that differ by several percent. A further complication that occurs with the truncated cone is that the input reactance doesn't vanish after the first few modes, nor does a standing wave occur with a pressure antinode at the inlet for more than the first few modes. Since experimental resonance curves are usually obtained by measuring the inlet pressure amplitude with a constant‐flow source, it is concluded that...