PRELIMINARY-RESULTS OF IN-FLIGHT EXPERIMENTS ON THE ACTIVE CONTROL OF PROPELLER-INDUCED CABIN NOISE

The purpose of this short note is to present the first results of a series of experiments undertaken on the active control of the sound field in the passenger cabin of a 48-seat propeller-driven aircraft. The measurements reported were undertaken during the first flight of the series which was held during March 1988 as part of a British Aerospace flight test programme. The aircraft used was a BAe 748 twin turboprop which was flown under straight and level cruise conditions. The sound field in the cabin was controlled using a system which employed 16 loudspeakers to minimize the sum of the squared pressures sensed at 32 microphones in a plane at seated passenger head height. The results from one configuration of the control system are presented here; they demonstrate significant reductions in the sound pressure level recorded at the 32 microphones used in the control system.