Body modes

Body modes are the resonances of the guitar body that originate from basic resonances of the (mostly) wooden structure, and some are coupled with resonances associated with the air cavity. The whole body and neck can oscillates like a bea: this is called the bending mode. There are important ones where the top plate, back plate and Helmholtz resonance of the cavity couple together to produce resonances around 100 to 300 Hz, and boost the bass response. Some great simulations are found here