Recent studies combining electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) have shown promising results by correlating EEG characteristics with the spatial information provided by fNIRS. The present study aims to analyze the topographical effect of auditory stimulus intensity on cortical activation using fNIRS and to correlate this hemodynamic response with auditory evoked potentials (AEPs) P1, N1, and P2 and their possible habituation. Forty volunteers (13 males, 27 females; mean age = 22.27 ± 3.96 years) participated in this study. The experimental section involved the presentation of complex tones of different intensities (50-, 70-, and 90-dB SPL) including 7 different frequencies (400, 850, 1150, 1650, 1950, 2450, 2750 Hz), in blocks of five stimuli, while EEG and fNIRS signals were recorded. Our results indicate that increasing sound intensity led to amplitude changes in AEPs, and enhanced neural recruitment in auditory and prefrontal cortices, as analyzed by fNIRS. Correlation analyses suggest a prefrontal source for the P2 component. In addition, the observed correlation between the habituation index and specific prefrontal cortex channels in the inferior and superior frontal gyri would suggest the involvement of cognitive resources in the habituation process to block stimuli. These findings provide insight into the relationship between auditory stimulus intensity and neural engagement, with potential implications for understanding auditory perception in both healthy and clinical populations.