FKB113

The MB Quart FKB113 is a pair of 5.25-inch two-way coaxial speakers made to drop into factory 5.25-inch openings in doors, dashes, and rear decks. Each speaker takes 45 W RMS and 90 W peak, for 90 W RMS and 180 W peak per pair, which covers stock head unit power and small four-channel amplifiers alike. A 1-inch aluminum dome tweeter sits on the center axis of the cone and carries response to 20 kHz, and a 4 kHz internal crossover with a 12 dB slope keeps the handoff from midrange to tweeter even. The thermal-formed polypropylene cone is light enough for fast midrange detail, and butyl rubber surrounds add mid-bass weight while shrugging off heat, cold, and moisture inside a door. A pure copper voice coil wound on a Kapton former builds strong magnetic force and dissipates heat, while over-coil cooling moves air across the coil through the epoxy-infused natural fiber spider. Heavy gauge progressive-die stamped steel frames stay rigid under full power, and a textured ABS gasket seals against the mounting surface to stop air leaks and panel buzz. Sensitivity is 88 dB, so volume comes easily without a large amplifier. The shallow 2-inch mounting depth is the standout for tight door cavities and dash pods where deeper speakers will not clear. Cutout is 4.48 inches with a 6.26-inch outside diameter, and connections take spade terminals or solder direct.