The present invention relates an audio-headset for acquisition of a bio-signal from a subject, comprising a first earpiece； a second earpiece； an arch connecting the first earpiece and the second earpiece； said arch comprising a hub (4)； wherein the arch, the first earpiece and the second earpiece are configured so that the earpieces are placed over a subject's ears when the audio headset is worn by the subject； and at least one posterior branch (1) having a first end extending from the hub and a second free end； the at least one posterior branch (1) comprising a concave surface with a radius of curvature, a collapsed state when the headset is not worn by the subject and an expanded state when the headset is worn by the subject.
