4-inch coaxial mobile audio loudspeaker

4" coaxial
10.16cm coaxial


$9995 per pair

Available Finishes:
Additional Images

Your Ride. Our Sound.

The DXi400 is an easy install in a door or in a dash. Its compactness makes it an easy fit, but it’s big on all the Polk technology that makes it uniquely DXi: Legendary Polk sound at a terrific price.

DXi400 Features:

Klippel motor optimization uses laser measurement technology to ensure a smooth excursion path at either end of the volume spectrum for uniform performance at both low and high volumes.

Polk’s proprietary, patented Dynamic Balance® technology allows our engineers to design out distortion-causing driver and system resonances, so you only hear the good sounds.

Composite cones feature tremendous stiffness-to mass ratio. Lower mass means faster transients and finer detail.

Marine Certified means the DXi400 is built tough to withstand the harshest environments on the water.

All Polk products are made using the best materials and the most advanced manufacturing techniques. They pass the industry’s most exhaustive quality tests, including drop testing, extreme signal response and UV & salt exposure testing. Polk loudspeakers are built to perform for a lifetime.

Driver Complement

Diameter3/4" (1.91cm) 
Typesilk dome 
Diameter4" (10.16cm) 
TypeDynamic Balance driver with polymer/mica composite cone 


Total Frequency Response85Hz-22kHz 
Nominal Impedance4 ohms
Efficiency91 dB
Power Handling
Continuous45 watts
Peak135 watts


Cut-Out Diameter3 11/16" (9.37cm) 
Height5/8" (1.59cm) 
Full-Range Mounting Depth
Top Mount1 3/4" (4.45cm) 
Bottom Mount1 15/16" (4.92cm) 


Unit of Measurepair 


Speaker Warranty1 year parts and labor (original purchaser) 

Specifications, dimensions and features subject to change without notice. For more information call us at 1-800-377-7655 (USA and Canada). Outside of North America call +1 (410) 358-3600.

DXi400 Media

DXi400 Accessories