Over-ear headphones (or around-ear headphones) are acoustic wearable devices that directly contact with the surface of the human body. In addition to the shape and material of the earmuffs, the clamping force applied to the earmuffs will directly affect the contacting force on the scalp and the noise attenuation performance, thereby influencing the user's wearing comfort and hearing comfort. To address the challenge of measuring and evaluating contact pressure in headphone products, a testing device was designed to employ an adjustable clamping force on a subject. In contrast, the contact pressure exerted on the scalp was measured using a pair of pressure-sensitive films. To analyze acoustic parameters during the wearing process, a pair of miniature microphones was positioned at the ear canal entrances to record and analyze the attenuation of binaural noise exposure dose (i.e. noise reduction amount) under different noise environments and various clamping forces. Finally, by incorporating comfort rating scales, the study examined the relationship between objective parameters including clamping force, contacting force and noise attenuation, and subjective comfort perception. Based on the findings, an appropriate range for clamping force design is suggested. The experimental methodology and relevant conclusions of this study provide a reference for the design and evaluation of clamping force in over-ear headphones.