Infinity REF407F 4" 2-Way Coaxial Car Speakers

The Infinity REF407F is a pair of 4-inch, 2-way coaxial car speakers designed to replace worn or limited factory speakers in compatible vehicle locations. Its compact footprint helps address upgrades where space behind the mounting surface is restricted. The pair combines a woofer and tweeter in each speaker for a straightforward full-range replacement solution.

These speakers are suited to listeners seeking clearer high frequencies and more defined everyday playback from a factory radio or properly matched aftermarket amplifier. With 35 watts RMS power handling per speaker, the REF407F is intended for modest-power car-audio systems. Its 92 dB sensitivity rating supports useful output from compatible source units and amplification.

The REF407F uses an edge-driven textile balanced-dome tweeter to reproduce upper-frequency detail. This tweeter design is paired with a polypropylene Plus One woofer cone and hi-roll rubber surround. The resulting coaxial layout keeps the system compact while covering a 75 Hz to 21 kHz frequency range.

Infinity's Plus One woofer cone architecture increases cone area compared with conventional cones of the same class. More radiating area can support sensitivity and low-frequency output within the speaker's size limits. For a 4-inch speaker location, this design helps make efficient use of the available mounting space.

The 3-ohm nominal impedance is designed for use with compatible car-audio equipment, while the integrated 4 kHz crossover point divides playback between the woofer and tweeter. This makes the REF407F a practical fit for replacing a factory coaxial speaker pair without adding separate external crossovers. Confirm vehicle fitment, mounting depth, and cutout dimensions before installation.

Key Features

• 4-Inch Coaxial Design: Combines woofer and tweeter in each compact speaker.
• 35W RMS Handling: Suits compatible factory radios or modest aftermarket amplification.
• Plus One Woofer Cone: Provides increased cone area in its class.
• Textile Dome Tweeter: Delivers clear, extended high-frequency reproduction.
• 3-Ohm Nominal Impedance: Designed for compatible car-audio power sources.
• Compact Mounting Profile: Fits locations with limited mounting depth.

Design & Installation

The REF407F uses a polypropylene Plus One woofer cone with a hi-roll rubber surround, paired with a 1/2-inch edge-driven textile balanced-dome tweeter. Its 4-inch coaxial construction integrates both drivers into a single assembly. The speaker has a 4-1/16-inch external diameter and a total depth of 2-3/16 inches.

Verify that the vehicle accepts a 3-11/16-inch mounting cutout and provides at least 1-7/8 inches of mounting depth. The package includes a pair of speakers, foam mounting tape, and an owner's manual; installation hardware is not listed. Use correct polarity and pair the speakers with a source unit or amplifier appropriate for their 3-ohm impedance and 35-watt RMS power rating.