The invention is disclosed herein in a method and apparatus for manufacturing a glass fiber mat. A fiber collecting surface is moved past a fiber deposition station. Glass fibers are provided, deposited, and processed in a mat-like mass on the collecting surface. Data is processed in a data processing means to obtain values representing the difference between the actual conditions and the desired conditions of the plurality of variables involved in the providing, depositing, and processing of the glass fibers to obtain a finished glass fiber mat with desired characteristics. The data processing means provides an operation change signal for at least one of the variables indicating the change necessary in a final control device for that one variable to eliminate a deviation between an actual and a desired condition for the variable. The operation change signal is stored in a supervisory control for the one variable, enabling more time for processing of data in the data processing means for the other variables being controlled. The operation of the final control device for the one variable is modified an amount dictated by the operation change signal stored in the supervisory control.