xoxos has released Acoustic, a freeware VST effect plug-in for Windows.
Acoustic is a simple acoustic body resonator model, consisting of a first order mass-spring for modeling the Helmholtz or ‘air’ frequency, and a banded waveguide.
Acoustic is a port of the body resonator model from the Boing2 bowed string synthesizer.
Visit xoxos for more information and a link to download Acoustic.