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Active noise control ( ANC ), also known as noise cancellation ( NC ), or active noise reduction ( ANR ), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first. The concept was first developed in the late 1930s; later developmental work that began in the 1950s eventually resulted in ...
Noise, vibration, and harshness ( NVH ), also known as noise and vibration ( N&V ), is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. While noise and vibration can be readily measured, harshness is a subjective quality, and is measured either via jury evaluations, or with ...
Rail squeal is a sound caused by a train's wheels slipping under specific conditions, usually around sharp curves. [4] Air displacement of a train in a tunnel can create noise from turbulence. Trains also use horns, whistles, bells, and other noise-making devices for both communications and warnings. The engines in diesel locomotives and DMUs ...
t. e. The rolling stock of the Bay Area Rapid Transit (BART) system consists of 782 self-propelled electric multiple units, built in four separate orders. [1] Pre- pandemic, to run a typical peak morning commute, BART required 579 cars. Of those, 535 are scheduled to be in active service; the others are used to build up four spare trains (used ...
Level crossing signals are the electronic warning devices for road vehicles at railroad level crossings . Level crossings can be operated in various ways. In some countries such as the UK, the warning devices are more often than not activated by remote control, I.e. an operator pressing buttons. However, the majority of countries have automated ...
Have you been awakened just after 4 in the morning by the clamorous dong-dong-dong of a light rail horn? Is living near the Regional Transit train tracks an almost-never-ending nightmare, except ...
Industrial noise control is a subset of interior architectural control of noise, with emphasis on specific methods of sound isolation from industrial machinery and for protection of workers at their task stations. Sound masking is the active addition of noise to reduce the annoyance of certain sounds, the opposite of soundproofing .
Roadway noise is the collective sound energy emanating from motor vehicles. It consists chiefly of road surface, tire, engine /transmission, aerodynamic, and braking elements. Noise of rolling tires driving on pavement is found to be the biggest contributor of highway noise and increases with higher vehicle speeds. [1] [2] [3]