The effective identification and control of powertrain structure borne harmonic noise is key to achieving a desired Noise Quality profile in a vehicle. Much work is being done in this field to refine and develop Sound Engineering techniques suitable for application at each stage of a vehicle development programme. For prototype development and trouble shooting, transfer path analysis and source identification techniques are in use today with varying degrees of success and application complexity. Investigation tools, which are fast, do not require extensive vehicle dismantling, and yet provide reliable answers will be of value to the NVH and Sound Quality Engineer. A new Active Path Tracking method is described which is relatively quick and offers practical confirmation of the influence of identified paths. The method involves the novel adaptation of Active Noise Cancellation techniques to the task of source identification. Powertrain mount input forces are derived and their relative importance ranked based upon their ability to recreate the operational sound field under investigation.
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