material within the batt in the event that a binder solution or slurry is utilized the coating operation may include a drying step to remove at least the majority of the water or other solvent before actually curing the binder composition the coating material 15 is applied to selected regions of the upper surface 11 of the fiber batt under conditions that ensure that the coating material is preferably distributed throughout the thickness of the fiber batt in a relatively narrow band depending on the characteristics of the fiber batt 10 such as thickness and open volume and the coating material 15 such as viscosity flowrate particle size distribution and ejection velocity a vacuum device 16 may be provided adjacent the rear surface 13 of the fiber batt to assist in the penetration of the coating material through the fiber batt although as shown in fig1 a common vacuum device 16 may serve a number of ejector heads 14 in the embodiment shown in fig2 each of the ejector heads is associated with a dedicated vacuum device 17 to provide additional control of the penetration of the coating material 15 as also shown in fig2 the coating material 15 may be applied to the fiber from the rear surface 13 preferably with a vacuum assist from a vacuum device 17 the availability of two sided coating allows full thickness coating of the fiber batt under operating conditions that would preclude a single sided application from achieving sufficient coating material.