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Exposure to low-frequency sound and infrasound is becoming increasingly common in modern environments, yet their neural processing remains insufficiently understood. This study investigates human auditory processing of low-frequency and infrasound stimuli using 64-channel electroencephalography (EEG), with a focus on late auditory evoked potentials (LAEPs), which reflect higher-order auditory processing in the brain. Acoustic stimuli were presented at an equal-loudness level of 70 phon across frequencies ranging from 500 Hz down to 4 Hz (infrasound) in a group of participants. LAEPs could be elicited by all presented frequencies, and source localization showed that brain responses differed between low-frequency and higher-frequency sounds in both spatial and temporal characteristics. In addition, a method was developed during this study to improve LAEP estimation in multichannel EEG recordings. These findings contribute to a deeper understanding of how the human brain processes sound near or below conscious perception and support the development of more robust EEG-based methodologies for investigating low-frequency auditory phenomena.