The APart CMSUB8 stereo ceiling subwoofer is designed to reproduce a fat and deep bass. Featuring dual 8 ohms coils and incorporated passive filter circuitry, the CMSUB8 can be used in almost any situation where extra bass is needed at low to medium sound levels and where interior decoration does not permit the installation of a subwoofer cabinet. This subwoofer is the ideal partner for all kinds of satellite speakers: small to medium APart CM speakers (CM3T, CM4T and many others) but also small cabinet speakers, such as the APart MASK4 (T). Due to the aluminum grille, this speaker is also suitable for use in humid conditions. Furthermore, to its discrete design (identically to many of CM speakers), can enjoy high quality background music with plenty of bass. Ideally, should use the CMSUB8 in an active configuration, for example by using Champ-4 amplifier with integrated active low- and high pass filters. In case use the CMSUB8 in passive speaker systems, make sure the satellite speakers have their own high pass filters, for optimum blending with the CMSUB8 speaker. If need more bass or when the room is acoustically troublesome, add more CMSUB-8 speakers and spread them across the area. The speaker is designed for infinite baffle use (e.g. into a ceiling), meaning that don't need to build a back box. When built into an enclosure (e.g. furniture), recommend a closed box with minimum 20L of volume.