The J-INFRA is a cardioid infra subwoofer designed to enhance J-Series systems, including J8, J12, and J-SUB cabinets, by extending the frequency response down to 27 Hz. It is intended for ground-stacked configurations in conventional left/right setups or arranged in an infra subwoofer array.

The J-INFRA features two bass-reflex chambers, each housing three 21" drivers. Two forward-facing drivers are powered by one amplifier channel, while the third rear-facing driver is powered by a separate amplifier channel. This setup creates a cardioid dispersion pattern, minimizing unwanted energy behind the system and significantly reducing low-frequency reverberation for highly accurate low-frequency reproduction. The amplifier's Hypercardioid mode optimizes front and rear channel tuning for maximum rejection at the left and right sides behind the cabinet.

Constructed from marine plywood with a Polyurea Cabinet Protection (PCP) finish, the J-INFRA is built to withstand impact and weather conditions. Both the front and rear of the cabinet are protected by a rigid metal grill, and the side panels include eight handles for easy transport. The cabinet front is equipped with four catches for securing an optional wooden lid.