Psychophysiological observations, especially PETCO2 and EEG, during relaxation training with deep-diaphragmatic breathing and mental imagery, suggest that the addition of certain types of music deepens breathing and quickens relaxation: PETCO2 normalizes with decreased respiration rate, and EEG shows decreased average theta and increased alpha. The combined psychophysiological indices suggest that music potentiates the hypometabolic counterarousal state. And clients unanimously report that they enjoy it.