The HPI-18LP compact 18" sub bass is a compact sub solution for the permanent installation and live sound touring market where a low profile sub bass is required. It is suited to midhigh sound pressure level bass and sub bass as a stand-alone unit or in combination with the 12" HPI212S sub bass as a multi-way or parallel sub bass system. The HPI18LP sub bass can be deployed as an additional sub bass enhancement to the HPI-110/210 speaker systems. It is equally at home as a standalone sub bass with any medium format speaker array or distributed system. The HPI-18LP can be flown using the box threaded inserts for permanent installation or as a mobile sub-satellite system using the internal 35mm top hat speaker pole fitting for adding a satellite speaker.