Infinity REF507F 5.25" 2-Way Coaxial Car Speakers

The Infinity REF507F is a pair of 5.25-inch coaxial car speakers designed to replace worn or basic factory speakers. Its compact format supports upgrades where space behind the factory grille is limited. The two-way design combines a woofer and tweeter in each speaker for full-range front or rear speaker positions.

These speakers are intended for listeners who want clearer high frequencies and more defined midrange from a factory-style speaker location. With 45 watts RMS power handling per speaker and 92 dB sensitivity, they can be used with a compatible factory radio or an aftermarket amplifier. Their 3-ohm nominal impedance is designed for compatible car-audio systems.

Infinity uses edge-driven textile tweeters to reproduce high frequencies with a smooth character. The Plus One woofer-cone architecture increases effective cone area compared with conventional cones in the same class. This design supports stronger low-frequency output and detailed midrange reproduction from a compact speaker size.

The REF507F covers a 67 Hz to 21 kHz frequency range, making it suited to everyday full-range music playback. It is a coaxial design, so the tweeter is integrated with the woofer rather than requiring separate tweeter mounting locations. The built-in crossover point is specified at 5 kHz.

Use the REF507F as a direct-size replacement where vehicle fitment and mounting clearance match its dimensions. It can serve as a simple speaker-only upgrade or as part of a broader system with an aftermarket receiver, amplifier, or subwoofer. Check vehicle-specific mounting, wiring, and grille-clearance requirements before installation.

Key Features

• 5.25-Inch Coaxial Design: Combines woofer and tweeter in each speaker for straightforward full-range replacement.
• 45W RMS Power Handling: Supports continuous power up to 45 watts per speaker.
• Edge-Driven Textile Tweeter: Produces smooth, clear high-frequency reproduction.
• Plus One Woofer Cone: Provides increased cone area for low-frequency and midrange output.
• 3-Ohm Nominal Impedance: Matches compatible car-audio amplifiers and receiver outputs.
• Optimized Compact Frame: Helps accommodate installation in many factory speaker locations.

Design & Installation

The REF507F uses a compact coaxial layout with an integrated edge-driven textile tweeter and a Plus One woofer cone. Its 5-1/8-inch external diameter, 4-1/2-inch mounting cutout requirement, and 1-15/16-inch mounting depth are important measurements for planning an installation. The pair includes foam mounting tape to help provide a secure mounting surface.

Confirm that the vehicle has adequate cutout diameter, mounting depth, and clearance behind the grille before ordering. Vehicle-specific speaker adapters, mounting hardware, and wiring harnesses may be required depending on the factory location and connector. Observe correct positive and negative speaker polarity, and match amplifier power responsibly to the 45-watt RMS rating per speaker.