The authors demonstrate that a class of ultrasonic metamaterial, which is composed of subwavelength resonant units built up by parallel-coupledelmholtz resonators with identical resonant frequency, possesses broadocally resonant forbidden bands. The bandwidths are strongly dependent onhe number of resonators in each unit. The broadening of bands is ascribedo the change of effective acoustic impendence. The coupling effects onhe wave vector and negative dynamic modulus are discussed. Numericalimulations by finite element method further confirm the theoreticalesults. © 2008 American Institute of Physics.DOI: 10.1063/1.2839401