Vibe OptiSound Auto 8 Active – 8 900W Slimline Passive Subwoofer Bass System. The VIBE Optisound range continues to advance what is possible from a compact bass solution with the OptiSound Auto 8 underseat subwoofer enclosures. These super slim bass enclosures are designed to fit in even the smallest of spaces whilst still having the big bass presence that people have come to expect from VIBE. Labyrinth slot ported bass reflex enclosure design increases efficiency, maximising bass output. Active enclosures have an integrated amplifier. VIBE’s PowerBox Bass amplifiers are perfectly matched to get the best possible performance from the Slick subwoofer and enclosures combination. VIBE’s revolutionary Anti Resonance Bass Support System A. R. B. Eliminates unwanted vibrations for more defined bass and integrated mounting brackets make it easy to secure to a suitable surface. Active: Integrated PowerBox 1 Amplifier.