Abstract: A structure includes a sound-generating element, a first combining member, a plurality of second vibration membranes, a plurality of spacing portions, a vibration space, and a sound-absorbing element. Based on the structure, the arrangement of the first and second vibration membranes can enhance musicality of low frequencies of the sound-generating element and can also ensure the clearness of middle and high frequencies to allow most of the hearing impaired to clearly hear, and this, together with the arrangement of a combination curvature and spacing portions, makes the transmission path of sound waves wider and also makes the sound more transmittable, while the sound-absorbing element provides dual functions of noise reduction and supporting to the second vibration membranes.