Article
Tuning the homogenization of a metamaterial guitar top plate radiation spectrum using air-filled fan bracings (en)
* Presenting author
Abstract:
In a Finite-Difference Time Domain (FDTD) model, the impact of a fan bracing on a metamaterial guitar top plate is presented where the fans are not solid but filled with air. To allow experimental validation, a rectangular top plate is modeled as a plate with a single fan placed at ten different positions on the top plate rectangular to the bridge. The fan is a rectangular hollow tube. The model includes plate, fan, and air column inside the fan. When driving the plate with an impulse, the radiated sound integrated at a virtual microphone position shows a much denser spectrum compared to the plate without such a fan, caused by the air inside the fan amplifying the plate vibration at the fan position, leading to unbalanced mode distribution and, therefore, reduced mode cancellation. When driving the plate with an FDTD string model, the spectral radiation integrated over all strings is strongly homogenized depending on the fan position. The results are compared to experiments of such a guitar using a microphone array of 128 microphones with back-propagation and varying fan conditions.