The noise of heated air jets is found to have characteristics different from the predictions of a theory which assumes moving quadrupole sources. Jet-noise spectra (in octave bands) were measured at selected directions from the jet axis, as well as at different jet velocities. For a fixed direction of radiation, the spectra at different velocities have similar shapes and fit a single curve, if intensity levels are adjusted proportionally to an Nth power of velocity and if frequency is adjusted linearly with velocity. The value N of the velocity power law agrees, for each direction of radiation, with a moving-dipole-source theory. The linear frequency dependence. however, shows no influence of the Doppler shift which is expected for moving sources.