This study explores the feasibility of using physiological signal processing to evaluate the relationship between auditory stimuli and mental states. Electroencephalogram (EEG) was collected from participants during alternating stress and relaxation tasks. Five types of auditory stimuli, including monaural beats and self-selected music, were introduced during rest periods to assess their impact on stress recovery. Results suggest that the AF7 channel was more responsive to auditory stimuli, indicating potential markers for real-time mental state monitoring. These findings support the development of objective, non-invasive stress assessment systems.