Recounts the career and contributions of Bob Aaron.

The object of the PAR meter is to provide a single number rating of the fidelity of a transmission system. Loudspeakers are members of this class and hence this meter can be used to evaluate them quantitatively. The rating is a weighted measure of the total gain and of phase distortion in the transmission system. This is a time-domain measuring set. The letters PAR stand for peak to (full wave) average ratio. The PAR meter measures the ratio of the peak to the full wave, rectified average value of a low-duty-cycle pulse signal. The test-signal spectrum used for this measurement can be tailored to produce the desired distortion sensitivities at various frequencies. Some of the results obtained in the use of this instrument in rating loudspeakers are presented here along with a discussion of its potentials.