String Bean

[ Making Violin a Better Sounding Instrument] -- violin acoustics that musicians/luthiers have to know

The vibration of a violin string is usually oversimplified as solely transverse mechanical vibration. In fact, longitudinal vibrations of density waves are always robustly excited, since both of them are gapless excitations. As coupled to many parts in violin and the non-linear effects, transverse and longitudinal modes are not orthogonal to each other. Those underlying physics is never considered in the violin acoustic community. Those invisible longitudinal waves have weak coupling to the bridge and always dissipates considerable energy to the tailpiece. How to refrain the energy loss and preserve the string energy becomes tremendously important for energy conversion proficiency in violin acoustics.

Now, String Bean® technology provides an unprecedented solution and develops a passive (unplugged) device. Installed under the tailpiece, the patented "String Bean® for strings” is mechanically designed to preserve more string energy of all frequency. Due to strong coupling between the longitudinal and transverse modes, the preserved energy is able to enhance desired transverse vibrations. As more energy transmits to the resonance cavity via the bridge, the enhanced plate vibration leads to more sound projection. This profound and novel acoustic modification can make strings react faster as they are plucked or bowed. Less energy dissipation leading to longer reverberation has been also demonstrated.

For more scientific data, download the paper from the Arxiv at Cornell University: https://arxiv.org/abs/2210.08920 "Preservation of the harmonic overtones in the violin family beyond Stradivari"