Abstract This study examines how internal bracing geometry influences the vibro-acoustic behavior of the oud soundboard. A three-dimensional finite element model of the instrument was developed and experimentally validated through impact-hammer modal testing. Fourteen bracing configurations, ranging from traditional ladder layouts to alternative geometries, were analyzed under identical material and boundary conditions. Structural response, modal characteristics, and acoustic radiation were evaluated using a coupled structural–acoustic simulation framework. To enable systematic comparison, six quantitative performance indicators were introduced to represent vibrational stiffness, stress distribution, acoustic radiation, structural–acoustic efficiency, modal balance, and overall acoustic effectiveness. The results show that bracing strongly governs the stiffness distribution, thereby shifting the modal spectrum and the soundboard’s radiation behavior. Increased bracing density raises low-order modal frequencies and enhances projection and spectral clarity, whereas reduced bracing favors stronger low-frequency motion and increased low-frequency content, but yields a less controlled response. No single configuration maximizes all criteria simultaneously; instead, each layout represents a distinct trade-off among tonal richness, projection, and mechanical robustness. Two sets of design targets were defined to reflect different performance priorities, enabling configurations to be ranked for either tonal uniformity or acoustic power. Among the tested layouts, two configurations consistently delivered the best combined structural and acoustic performance across both target sets. Sensitivity analysis confirmed that these rankings are robust to moderate variations in the evaluation thresholds.
Abdallah et al. (Sat,) studied this question.