A plurality of NAS heads 1 to 4 can access a shared LU 18 which stores a shared resource 21 and a count value for the NAS head 1. The compounds, and compositions containing the compounds, can be used to treat a variety of central nervous system disorders such as schizophrenia. The opening length of the pair of second sound holes, which are in the sealing members on the opposite surface to the microphone housing side thereof, in a second direction perpendicular to a first direction in which the first sound holes are aligned, is larger than the opening length of the first sound holes in the second direction, which are on the major surface of the microphone housing. The method further includes determining calibration parameters that place closed loop poles of a composite system at the target closed loop poles. A dynamic programming matching technique is preferably used having constraints which depend upon whether or not the two sequences are generated from text or speech and in which the scoring of the dynamic programming paths is weighted by phoneme confusion scores, phoneme insertion scores and phoneme deletion scores where appropriate.