Abstract: A speaker includes a box-shaped enclosure, a speaker unit and a sounding board. A pair of side plates, a bottom plate, a top plate, a back plate and a baffle are assembled into the enclosure. The speaker unit is attached to an opening portion of the baffle. The sounding board is attached to the bottom plate, and includes a member having a fiber direction in a vibration direction of a vibrating plate, a member having a fiber direction in a direction which approaches the side plate (of the front side) as extending from a side of the back plate to a side of the baffle, and a member having a fiber direction in a direction which approaches the side plate (of the back side) as extending the side of the back plate to the side of the baffle.

Abstract: A voice coil includes a cylindrical bobbin formed of a first material; a coil which surrounds on an outer circumferential surface of the bobbin; and a plurality of reinforcement members formed of a material having a propagation speed faster than the first material and provided on the outer circumferential surface of the cylindrical bobbin.

Abstract: A voice coil includes a bobbin formed of a wooden sheet obtained by slicing natural wood to a predetermined thickness and a coil that surrounds an outer circumference of the bobbin.

Abstract: An acoustic diaphragm includes a diaphragm formed of a uniform material and a first standing wave suppression member provided on a surface of the diaphragm along a first direction of passing through a center of the diaphragm.

Abstract: A speaker system includes a speaker cabinet having a unit mounting port; a speaker unit attached to the unit mounting port; a sound absorbing structure disposed at a rear portion side of the speaker unit and in the speaker cabinet. The sound absorbing structure includes a porous air-permeable bag and flaky wood chips provided in the bag.

Abstract: An optical dispersion element for obtaining a spectrum image of an image observed via an optical microscope, has two wedge glass substrates which are formed to be overlaid so that their wedge points are directed in opposite directions, and have different dispersion properties.