The Ford LTD rear deck lid accommodates a 6x8 inch speaker size and 6x9 inch speakers, with both locations supporting these 2 unique sizes across the model's production span. Full-range units represent the compatible audio system type for all configurations. These specifications cover the years 1980 through 1986.
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 surface-mount location positioned at the base of the rear window, above the trunk cavity, where speakers fire upward into the passenger cabin.
Mounting in a rear deck lid typically places the speaker at a distance from front passengers, which affects stereo imaging and requires the speaker to project sound forward through the cabin.
The Ford LTD rear deck lid accommodates 2 distinct oval speaker sizes across the 1980-1986 model years: 6x9 inch and 6x8 inch.
A 6x9 inch oval speaker has a larger cone surface area than a 6x8 inch unit, which allows for greater air displacement and typically deeper low-frequency reproduction in a rear deck position.
The 6x9 inch size is specified for the 1980 and 1981 model years, and the elongated oval geometry of the driver suits the rear deck lid cutout dimensions of those vehicles.
A 6x8 inch oval speaker has a slightly reduced cone area compared to a 6x9 inch driver, and in a rear deck location the difference affects the lower boundary of bass extension the speaker can physically produce.
The 6x8 inch size is specified for the 1982 through 1986 model years, indicating a change in the rear deck lid cutout dimensions starting with the 1982 Ford LTD.
Full-range speakers reproduce the full audible frequency spectrum from a single driver, covering bass, midrange, and treble without requiring a separate crossover network or additional speaker components.
In a rear deck lid location, a full-range driver handles all frequency content without supplemental tweeters mounted nearby, meaning the single oval unit manages high-frequency dispersion as well as low-frequency output from that position.
The rear deck lid surface is generally a rigid, panel-based structure that can act as a baffle, and the coupling between the speaker and the deck surface influences the low-frequency loading of the driver.