The Tannoy CMS 603 PI 16 OHM BACKCAN is a dedicated pre-installation back canister designed specifically for the Tannoy CMS 603 PI series of in-ceiling loudspeakers. Its primary function is to provide a sealed, rigid, and properly tuned enclosure for the speaker driver within the ceiling void, which is critical for achieving optimal acoustic performance. When installed during the construction phase before drywall is applied, it creates a defined, airtight cabinet that isolates the driver from the unpredictable and often lossy environment of the ceiling plenum. This isolation prevents acoustic short-circuiting, where sound waves from the back of the driver cancel out those from the front, resulting in weak and undefined bass. The back can ensures the speaker performs to its designed specifications, delivering tighter, more accurate, and extended low-frequency response.

Constructed from durable, acoustically inert materials, the back can is engineered for secure mounting between ceiling joists. It typically features a robust design with integrated brackets or flanges that attach directly to the framing, providing a stable platform for the speaker baffle. The 16-ohm designation indicates it is matched to the impedance of the compatible CMS 603 PI speaker models. By creating a controlled volume, it also protects the speaker components from dust, insulation fibers, and moisture, contributing to the longevity and reliability of the installation. The paintable grille and baffle of the main speaker assembly then attach to this solid foundation, resulting in a clean, flush finish with the ceiling.

This accessory represents a best practice for high-fidelity in-ceiling installations, particularly in custom integration and commercial projects where audio quality is paramount. It transforms what would be a simple baffle-mounted driver into a true loudspeaker system with a proper enclosure, allowing the CMS 603 PI speakers to deliver their full sonic potential with consistent, predictable performance. For installers and specifiers, using the BACKCAN is essential for realizing the intended sound quality and ensuring customer satisfaction in premium audio installations.