 Dr. Decker said the most responsive possible guitar soundboard would be one with infinite stiffness and zero mass, so that the energy from the slightest tug of a finger on a string would translate most efficiently into moving air instead of diffusing as heat in the structure of the instrument.RainSong offers five different body styles of their guitars within several different “series”.Their body types they offer which are shown in the graphic below are the DR(dreadnought), the JM, The OM, the WS, and the PA. Each is designed for a different effect and sound quality.