title: A hybrid active/passive exhaust noise control system for locomotives.
abstract: 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 electret microphones 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.
authors.affiliation: BBN Technologies, Cambridge, Massachusetts 02138, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Remington
authors.forename: J Scott
authors.initials: JS
authors.lastname: Knight
authors.forename: Doug
authors.initials: D
authors.lastname: Hanna
authors.forename: Craig
authors.initials: C
authors.lastname: Rowley
mesh_terms: D000161:Acoustic Stimulation; D000465:Algorithms; D000669:Amplifiers, Electronic; D004581:Electronics / Q000295:instrumentation; D006801:Humans; D008962:Models, Theoretical; D009038:Motion; D009622:Noise; D013018:Sound Spectrography