Active control of payload fairing noise

This work presents adaptive feedforward control using advanced structural–acoustic actuators to reduce the low-frequency acoustic transmission in a sub-scale composite fairing. The actuators, referred to as distributed active vibration absorbers, are multi-resonance devices specifically designed to produce high output forces over a large bandwidth as necessary for payload fairing noise control. Single- and multi-channel control configurations were implemented using external acoustic disturbance levels as high as 130dB. Design parameters such as sample frequency, control filter length, reference source, and causality/delay were examined to determine impact on performance. The active control system reduced the broadband interior noise levels by up to 5dB between 70Hz and 200Hz, and 10dB at specific resonances.