As Acoustic engineer my advice is first to determine what frequency range you want to dampen (for example 20Hz -100Hz) and then find a material that is suitable. I know that sounds trivial but most people just start throwing names before even analyzing the problem. To find the suitable material I would check the transmissibility curves of different materials. A transmissibility graph is basically an input/output graph; everything above "1" means that you get amplification and below "1" means damping. Obviously you don’t want any resonance peaks in the region that you want to improve, otherwise you can end up making things worse. By comparing the graphs of different materials you can select the one that provides the most damping in the frequency region of interest. Those transmissibility measurements are really basic and any serious company should be able to provide you with those graphs. If they don’t I would question their seriousness.
Damping to exitation of parasitic modes of
What is the best material to use as a substrate for making Isolation plinths/platforms, for damping the excitation of parasitic modes of vibration as well as HF resonance? That looks cosmetically appealing as well?