A structure for a musical instrument body that limits vibration of various components or parts of the body while controlling and providing for overall resonance of the instrument. The structure is suitable for use with a musical instrument, specifically an electric guitar. The structure includes a support member or block positioned in a chamber created between a top plate and bottom plate of the guitar body and a structural element, spaced from the top and bottom plates, that engages the block to provide additional support and stiffness enabling further control of the overall vibration and thus resonance of the instrument. Varying the design of the structure along with the various body components provides an apparatus for uniquely tuning the acoustic characteristics of the guitar body.