A power efficient, acoustical Helmholtz resonator foghorn including a plurality of electrical emitters, some of which are redundant, arrayed at one end of a blocked tube with a plurality of exhaust ports located therein surrounded by a standoff tubular member. The foghorn tuned to provide a high pitch thus providing a compact horn having an acoustical path capable of producing an exceptional wavelength in a generally concentric horizontal sound propagation the horn configurable for use as either a one-half mile or two mile marine navigational aid for offshore structures, buoys, and the like.