JL Audio
4" 2-Way Full Range Speakers

JL Audio C1-400x
JL Audio C1-400x JL Audio C1-400x JL Audio C1-400x JL Audio C1-400x JL Audio C1-400x


C1 speakers deliver real substance and great audio performance in a format designed for easy fit behind factory grilles.

Component Woofers

C1 woofer drivers benefit from proprietary FEA modeling and JL Audio's expertise in low-frequency driver design. This knowledge is used to create speakers that can play loudly, while maintaining a smooth, dynamic, low distortion sound.

At the core of the C1-400x is a proprietary, stamped, steel 4-inch (100 mm) frame and a DMA-optimized motor system.

A mineral-filled, injection-molded polypropylene cone is suspended with a rubber surround on the front, and a carefully engineered spider at the top of the voice coil, to precisely control motion and prevent impact between the voice coil and the back plate.

Tinsel leads are carefully routed and attached to the spider to prevent fatigue and buzzing. These are the same kinds of features and materials normally found on much more expensive loudspeakers.


Equipped with a true, edge-driven, aluminum dome tweeter, C1 speakers stand further apart from others in its category with superior high-frequency clarity and definition.

The tweeter’s design has inherently excellent off-axis response and high-frequency extension. It also benefits from the damping of a silk surround suspension and Ferrofluid in the voice coil gap, along with the superior strength of a neodymium magnet circuit.

A true, 2nd order high-pass filter is employed to further enhance smoothness and improve power handling.

Vehicle Fit

To facilitate fit, breakaway mounting tabs on the woofer frame allow the C1-400x to be installed in four-hole or two-hole mounting configurations.


Recommended Amplifier Power
10 - 50W RMS / Channel
84.5 dB @ 1 W / 1 m
Nominal Impedance
Frequency Response
64Hz - 24kHz ± 3dB
Frame Outer Diameter (A)
4.03” / 102 mm
Grille Tray Outer Diameter (B)
Motor Outer Diameter (C)
2.33” / 59 mm
Frontal Coaxial Tweeter Protrusion (D)
0.61” / 16 mm
Frontal Grille Protrusion (E)
Mounting Hole Diameter (F)
3.7” / 94 mm
Mounting Depth (G)
1.81” / 46 mm
More Information
Brand JL Audio
RMS Power 35W RMS
Speaker Design 2-Way
Speaker Size 4"