Infinity Primus 503CF 5.25" 2-Way Component Speakers

The Infinity Primus 503CF is a 5.25-inch, 2-way component speaker system designed to replace factory speakers with separate woofers and tweeters. It is intended for vehicle owners who want a more flexible front-stage upgrade than a coaxial speaker can provide. The set includes external in-line crossovers to route appropriate frequencies to the woofer and tweeter.

Each side is rated for 50 watts RMS and 150 watts peak, with a 3-ohm nominal impedance. The system has a 91 dB sensitivity rating measured at 2.83V/1m and a stated frequency response of 75 Hz to 20 kHz. These specifications make it suitable for use with a compatible factory or aftermarket radio, or with a properly matched external amplifier.

The 5.25-inch woofer uses a polypropylene cone with Infinity Plus One cone architecture and a rubber surround. The design increases usable cone area relative to conventional cones of the same class. Its compact mounting format can be useful where a larger speaker will not fit.

Separate 3/4-inch silk-dome tweeters use an edge-driven design to handle upper-frequency detail. The supplied crossovers use a 5 kHz crossover point with a 12 dB-per-octave slope. With the tweeters mounted higher in a door, dash, sail panel, or factory location where appropriate, the system can support more focused high-frequency placement than a single-point speaker arrangement.

A vented basket frame is designed to help move heat away from the woofer motor structure during operation. The set is finished in black and includes hardware and multiple tweeter-mounting pieces for installation flexibility. It is a practical choice for a vehicle-specific 5.25-inch component upgrade when mounting depth, cutout size, and electrical compatibility have been verified.

Key Features

• 5.25-Inch Component System: Separate woofers and tweeters support flexible speaker placement.
• Plus One Cone Architecture: Provides increased cone area for its class.
• Silk-Dome Tweeters: Handles high frequencies with an edge-driven design.
• 3-Ohm Nominal Impedance: Designed for compatible factory or aftermarket power.
• External In-Line Crossovers: Directs frequencies between woofers and tweeters.
• Vented Basket Frame: Helps manage heat around the woofer motor.

Design & Installation

The Primus 503CF combines polypropylene woofer cones, rubber surrounds, silk-dome tweeters, and rigid vented woofer baskets. The woofer mounting depth is listed at 1.81 inches, while the top-mount cutout requirement is listed at approximately 4.5 inches. No speaker grilles are included with this component system.

Confirm the vehicle's factory opening, mounting depth, mounting height, and available tweeter location before purchase. Install each woofer and tweeter through its supplied in-line crossover, observing polarity and keeping the crossover protected inside the vehicle. The package includes flush-, surface-, and starfish-style tweeter mounting hardware, but vehicle-specific brackets, wiring adapters, or panels may still be needed.