NORMALITY OF A FAMILY OF BANACH-VALUED HOLOMORPHIC MAPS

A device for measuring the acoustic absorption properties of materials such as liners for jet engines has a first housing, an acoustic driver configured to provide acoustic energy to the first housing, a second housing attached to the first housing, and an acoustic driver configured to provide acoustic energy to the second housing. Acoustic sensors are used to measure the acoustic energy emitted from the two housings and to measure the absorption of each of the housings.