MQ 90S is a compact band-pass 8 inch subwoofer. It can be connected through a removable Euroblock plug that allows the parallel connection of other loudspeakers. The cabinet material is MDF with a scratch resistant surface. The subwoofer has internally a transformer for constant voltage lines (100 or 70 V). The power selection is made by means of its selector. It is for indoor use only (avoid to use it in very humid places). It should be put on the floor of a room where “satellite” loudspeakers (for mid / high frequencies) are already present. MQ 90S belongs to RCF monitor Q series.