One of the main goals of sonic crystals research is the search of systems with large gaps. Here we report on the enhancement of full gaps induced by the reduction of the symmetry in two dimensional sonic crystal. This effect has been studied in triangular and square arrangements of rigid cylinders in air. For square lattices the symmetry reduction is achieved by a smaller cylinder put at the center of each unit cell. For triangular lattices the symmetry reduction is studied by decreasing the diameter of the cylinder at the center of hexagons in the lattice. Zero order transmission experiments has been performed in order to prove the theoretical predictions. In particular, we have experimentally studied a honeycomb triangular transition by putting rods of increasing diameter at the center of hexagons: Starting with a honeycomb lattice with cylinder's diameter size d1 we have studied the behavior of gaps as a function of the cylinder ratio d2/d1, being d2 the variable diameter! of the c