As a method of fabricating aspherical microstructures, a protruding microstructure is formed on a substrate, an aspherical-profile forming layer is formed on the substrate and the protruding microstructure, and the aspherical-profile forming layer is hardened. The feedback terminal is connected between the register and voltage generator. For the separation of the test signals and the audio signals a test adapter is used which is coupled between the appliance, the control computer and an amplifier for the audio signals. The bypass means is positioned on one of the plurality of walls facing away from the front side and is adapted for selectively providing a through-flow opening with an adjustable opening area to the surrounding of the galley assembly. In other embodiments, the back support portion may include a similarly configured back cushion.