Index of content:
Volume 117, Issue 1, January 2005
- APPLIED ARTICLE-NOISE: ITS EFFECTS AND CONTROL 
117(2005); http://dx.doi.org/10.1121/1.1836851View Description Hide Description
A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2–12-in. speakers per enclosure as actuators, eight roof-mounted electretmicrophones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal.