Problem: Most rooms/cabins have dimensions that favor standing waves (resonant modes) which are in the range of vibration frequencies of the propulsion engines, gensets, or other machinery on board watercraft. undesirable and unfortunate coupling of the room acoustic modes with the machinery vibration frequencies results in boom/rumble in the room. such low-frequency noise, which is […]
Read MoreIn four stroke engines, including diesel engines driving generators, each cylinder fires every other revolution. This causes the engine vibration to occur at ½ the engine RPM, called the ½ order vibration, and its higher order harmonics namely 1 order, 1½ order, 2 order. In the case of a diesel generator, in addition to the […]
Read MoreHunter’s Point South Park is a breath-taking waterfront park located on the edge of the East River, in Western Queens, NY. The focal point of the park is Hunter’s Point South overlook, a beautiful cantilevered platform that offers unobstructed views of the New York skyline. The Overlook’s rather low fundamental frequency (3.5 Hz) combined with […]
Read MoreGrant Street Pier, the focal point for “The Waterfront” development in Vancouver, WA is an attractive, triangular, post-tensioned concrete deck overhanging the water by 90 feet providing an expansive view of Columbia River. A cable system and 80-foot-tall mast support the deck. Since the pier is intended for visitors walking on it as well as […]
Read MoreLarge vehicles, such as SUVs (Sport Utility Vehicle) and minivans, exhibit body boom phenomena during multiple source excitation events including rough road/impact and powertrain induced events. The main cause of the boom is the low-frequency acoustic/vibro-acoustic modes of the cavity being excited via the high acoustic transfer functions at multiple paths, due to an inherently […]
Read MoreReactive absorbers, such as Helmholtz resonators (HR) or quarter-wave tubes, are commonly used as the most effective solution for abating the low-frequency tonal noise in many applications including the quieting of air intake induction system noise in internal combustion engines. The problem with these low-frequency absorbers is their large size. In addition, reactive absorbers can […]
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