The Mercury Milan rear deck lid accommodates a 6x9 inch speaker size across all listed model years. Full-range units represent the compatible type for the audio system in that location. These specifications cover the 2006 to 2011 model range.
A single driver that reproduces bass through treble without a separate crossover network. It is the simplest replacement option and is common in factory audio systems.
Additional Notes
The rear deck lid is a horizontal mounting surface positioned at the back of the cabin, behind the rear seats and above the trunk cavity, placing speakers in a rearward-facing or upward-angled orientation relative to passengers.
Mounting at the rear deck lid places speakers at a greater distance from front-seat occupants, a position where larger driver surface areas help maintain perceived volume and clarity across the cabin.
The Mercury Milan accommodates 6x9 inch speakers at the rear deck lid position across all 6 model years in the specifications, from 2006 through 2011.
A 6x9 inch oval driver has a larger radiating surface area than round mid-range drivers, which allows greater air displacement and stronger low-frequency output relative to more compact sizes.
The elongated oval shape of a 6x9 inch driver is a common fitment for rear deck locations in sedans, where the available cutout dimensions are wider than they are deep due to structural constraints in the trunk lid panel.
At the rear deck lid position, the trunk cavity beneath the mounting surface can act as an unintended acoustic chamber, and the mechanical properties of a 6x9 inch driver include a cone and surround designed to handle the resonant interactions typical of such enclosed or semi-enclosed spaces.
Full-range speakers are single-driver units engineered to reproduce a wide portion of the audible frequency spectrum, generally spanning from the lower bass frequencies up through high-frequency treble content.
A full-range driver at the rear deck lid position handles bass, midrange, and treble simultaneously without the need for a separate crossover network or additional drivers at that location.
The rear deck lid placement positions full-range speakers so that high-frequency output, which is inherently directional, projects toward the headliner and cabin interior rather than directly at seated passengers, affecting the perceived treble balance from the rear channel.
Full-range compatibility at the rear deck lid indicates a single-driver solution is sufficient for the Mercury Milan's factory speaker opening dimensions at that location, without requiring component speaker configurations involving separate tweeters and woofers.