A pulsed spectrophone has been developed to study vibrational energy transfer processes in gases. CO2was chosen as the test gas to allow comparisons with other methods. The spectrophone proves to be a powerful tool to measure relaxation rates and study relaxation pathways when coupled with other measurement techniques. All the micro‐ and macroscopic processes which affect the spectrophone response must be considered simultaneously in order to interpret the measured temporal evolution of pressure following excitation. Formulas which include a generalized treatment of multilevel systems and important macroscopic processes are presented. The experimental data are represented in terms of characteristic times of the pressure waveform and amplitudes of pressure changes. At intermediate (20 Torr and above) pressures, collisional energy transfer rates and mechanisms have the greatest influence on computed waveforms. Spontaneous emission has an obvious effect on the zero pressure intercept of the characteristic times. Acoustic propagation and thermal conduction determine the rate at which the gas, once perturbed, returns to equilibrium; at intermediate and higher pressures, acoustic propagation is found to be most important. The assumed rates of energy transfer and the relaxation mechanisms are varied to give computed pressure waveforms which agree with the measured spectrophone response (characteristic times and amplitudes), and which are simultaneously consistent with measurements using other techniques. This process indicates that the path of energy transferred from CO2(001) to CO2(040) is consistent with all experimental observations.