The　lattice　configurations　are　used　to　produce　the　different　effects　of　band　gap.　Based　on　the　well-known　ultrasonic　immersion　transmission　technique,　the　experimental　investigation　of　acoustic　wave　propagation　in　two-dimensional　phononic　crystals　for　square,　honeycomb　and　(4.82)　lattices　of　steel　rods　in　water　is　reported　at　the　same　normalized　radius.　Using　the　plane-wave　expansion　method　we　calculate　the　band　structures　of　phononic　crystal.　The　configurations　of　square,　honeycomb　and　(4.82)　lattices　have　an　atom-rods,　two　atoms-rods　and　four　atoms-rods　per　unit　cell　respectively.　We　found　the　structure　of　(4.82)　lattice　can　have　the　advantage　over　other　lattice　structures　and　open　the　very　lower-frequency　complete　band　gap.　Also,　a　good　agreement　between　experimental　results　of　complete　band　gaps　for　three　lattices　phononic　crystals　and　theoretical　predictions　is　obtained.　Thus,　the　(4.82)　phononic　crystal　may　help　to　design　the　new　controlling　materials　in　lower-frequency　ranges　as　noise　barriers.　©　2011　IEEE.