Abstract: An acoustic ear muff includes a pad or cup (2) which is made of rigid material and incorporates an opening for receiving one ear of the wearer, and a resilient sealing annulus (10) intended for abutment with the head of the wearer, and also resilient pressure-exerting means (5) connected to the shell of a protective helmet (1), a head strap or like head gear. The ear muff provides good acoustic damping and a high degree of comfort, owing to the fact that the resilient pressure-exerting means is configured to produce a low pressing force substantially independently of head sizes which vary within given limits. The pressure-exerting means includes, to this end, a spring element in the form of a combined torsion and bending spring.