Developments in active control of aircraft interior noise—Directions for tonal and broadband noise sources

Abstract

Aircraft interior noise is a continuing problem for a wide range of aircraft types. Interior noise levels in general aviation aircraft make communication difficult, significantly impact pilot endurance, and are considered important to the reemergence of this class of aircraft. For passengers in propeller-powered commuter aircraft, conversation is difficult at best and becomes oppressive on the passengers for long periods. It is also regarded as one reason for the replacement of propeller commuter aircraft by the emerging regional jet. In business jets, the passengers are often interested in conducting meetings during flights. This calls for low SPL and SIL for which the aircraft incurs both space and weight penalties. Large commercial aircraft pay a significant weight penalty for current interior noise levels considered acceptable. With the drive for more weight-effective airframes, the challenge becomes even more difficult. This paper will show some current efforts to develop more efficient active control technologies for both tonal noise sources and broadband noise sources. These will include improvements in controller technologies, actuator implementation, optimization of transducer topology, improved coupling to the noise source, and integration of the active technology with conventional passive technology.