Abstract: The invention relates to a soundboard for acoustic guitars. Until now, empirical-type criteria have been used to construct soundboards (8) for acoustic guitars, however, the invention employs physical and harmonic frequency criteria by taking account of the technological characteristics of the woods used to construct the soundboard (8). According to the invention, tension compensation is provided by distribution in a bent structure (bent fan bracing (13)) or with floating fan bracing (12) which is glued on top of the bent fan bracing (13) such as to enable the board to vibrate, while simultaneously conferring mechanical strength on same in the direction of pull. In this way, the invention relates to the use of bent fan bracing (13) which is glued to the soundboard (8) perpendicularly to the grain of the wood (16), such as to delimit different wood grain (16) lengths, defining what has been described as harmonic uses of frequencies (15).