In 1990, Khosropour and Millet reported on a study of the internal spectrum of a Helmholtz resonator excited by an air jet and reported that the data for frequency and amplitude of the Helmholtz mode as a function of jet speed show a series of domains separated by narrow transition regions [JASA88, 1211–1221 (1990)]. The idea was to observe the behavior of the air jet when the resonator effectively has just a single mode, and does not overblow to higher frequency modes at moderate jet velocities. Further research explored the effects of changes in neck length and jet angle, but higher resonator modes were ignored. This paper presents characterizations of some of the higher modes of cavity vibration, which can be excited at high jet velocities. Unlike the Helmholtz mode, these modes depend on the shape of the cavity shape as well as the volume. Several of these modes were observed, sometimes with more than one mode sounding simultaneously. Guided by finite element simulations, the nature of these higher cavity modes was verified experimentally by observing frequencies and locating nodal surfaces.