The bracing effect of the composites of polyurethane foam reinforced anisotropically with carbon fibers of top boards, was investigated. The frequency responses of boards were measured in the form of a transfer function by sweeping frequencies with an FFT analyzer. Sand was scattered on the face of the board to obtain Chladni characteristics. Modal analysis of the boards was completed using the FEM program, ANSYS. Physical values of Sp were utilized for analysis. Tetrahedral elements were utilized for meshing models. The vibration modes of the board was simulated integrated with guitar design. The differences in eigenfrequency in the wooden board with no bracing were also analyzed. Results show that top boards can be made effectively using composite materials without wood construction.