The JBL MTC-300BB12 is a specialized, sealed back enclosure engineered to provide optimal acoustic performance and installation flexibility for JBL Control 300 series 12-inch transducer assemblies in custom architectural projects. This backbox is not a speaker itself, but a critical accessory that creates a properly sized and sealed cabinet when paired with a compatible Control 300 series 12-inch driver and grille. It is designed for integrators and architects who require a high-performance, full-range loudspeaker solution that can be seamlessly and invisibly built into walls, ceilings, or custom cabinetry, delivering the acoustic integrity of a premium studio monitor within a bespoke architectural environment.

Constructed from high-density, internally braced medium-density fiberboard (MDF), the backbox is acoustically inert to prevent unwanted resonances that could color the sound. Its precise internal volume of three cubic feet is calculated to match the specific Thiele/Small parameters of the 12-inch Control 300 drivers, ensuring correct bass tuning and linear frequency response. The sealed (acoustic suspension) design provides tight, accurate bass reproduction and protects the driver from environmental contaminants. The box includes pre-cut mounting holes and a robust gasketing system to ensure an airtight seal when the driver is installed, which is essential for maintaining the intended low-frequency performance and overall sonic accuracy.

Installation is designed for professional custom integration. The backbox is built to be installed during the construction or renovation phase, secured within a wall or ceiling framework before the final surface material (such as drywall, wood, or fabric) is applied. A compatible JBL perforated metal grille or custom acoustically transparent fabric can then be stretched over the opening, allowing the speaker to become a completely invisible part of the architecture. By providing a precisely engineered acoustic environment for the high-output 12-inch driver, the JBL MTC-300BB12 Backbox enables the creation of powerful, high-fidelity distributed audio or home theater systems that prioritize both sonic excellence and complete visual discretion.