It is shown that sonic crystals consisting of cylindrical rods made of rubber crumb can be used as efficient structures to attenuate noise in a wide range of frequencies. A structure made of three rows of cylinders (3‐m height) has been fabricated and its isolation properties have been characterized in a transmission chamber. Two different numerical algorithms have used to simulate the experimental characterization. A good agreement between theory and experiment is obtained and gives support to design barriers based on this technology. [Work supported by MICIIN of Spain.]