Acoustin structure of seat back

An acoustic structure of seat back, comprising:

• a padding provided in said seat back, said padding having a forward side situated forwardly of the seat back;
• a backward side situated backwardly of the seat back;
• a hole defined therein;
• and a seat back frame provided therein;
• an acoustic unit including:
• at least one speaker means having a forward side from which a sound is to be emitted and a backward side;
• and a support box in which said at least one speaker means is supportively received, wherein said support box has:
• an opened side toward which said forward side of said at least one speaker means faces;
• and a backward wall opposite to said opened side, said backward wall facing to said backward side of said padding;
• said support box being accommodated in said hole of said padding such that a whole of said acoustic unit is disposed in said hole of said padding and that said opened side of the support box faces to the same direction as said forward side of the padding;
• a speaker support cushiony element having a forward wall facing forwardly of said seat back and a backward wall facing backwardly of said seat back, said speaker support cushiony element being securely accommodated in said support box such that the backward wall thereof faces to said backward wall of said support box;
• said at least one speaker means being resiliently supported in and by said speaker support cushiony element such that the forward side of said at least one speaker means is disposed at the same direction of said forward wall of said speaker support cushiony element;
• a sound-conductive cushion element which is juxtaposed and fixed on said speaker support cushiony element, while being supported by said support box, in such a manner that one side of said sound conductive cushion element faces to the same direction as said forward side of said padding, whereas another side of the sound-conductive cushion element faces to said forward wall of said speaker support cushiony element as well as to said forward side of said at least one speaker means;
• and
• a trim cover assembly covering said padding and said one side of said sound-conductive cushion element.