Infinity REF307F 3.5" 2-Way Coaxial Car Speakers

The Infinity REF307F is a pair of 3.5-inch, 2-way coaxial car speakers designed to replace worn or limited factory speakers in compact vehicle locations. Its round 3.5-inch format suits applications where available mounting space is restricted. Each speaker combines a woofer and tweeter in one assembly for a straightforward full-range speaker upgrade.

These speakers are intended for drivers who want clearer everyday music reproduction from a compatible factory or aftermarket audio system. With 25 watts RMS power handling per speaker and 91dB sensitivity at 2.83V/1m, the REF307F is sized appropriately for modest-power amplification. Its 3-ohm nominal impedance is designed to work with typical automotive speaker wiring and compatible source units or amplifiers.

The REF307F uses an edge-driven textile tweeter to reproduce high frequencies and a Plus One polypropylene woofer cone for the lower and midrange portions of the signal. The two-way coaxial layout keeps the drivers aligned in a compact assembly. Frequency response is rated at 85Hz to 21kHz, making these speakers suited to upper-range and full-range factory replacement positions rather than dedicated deep-bass duty.

Infinity's Plus One woofer-cone architecture increases usable cone area compared with conventional cone geometry in its class. In practical terms, the design supports efficient output and low-frequency presence from a small speaker footprint. A rubber surround complements the polypropylene cone for a durable moving assembly.

The REF307F can be used as part of a staged factory-system refresh, including dashboard, rear-panel, or other compatible 3.5-inch locations. Its 1-7/16-inch mounting depth and 3-inch cutout requirement should be checked against the vehicle before purchase. For systems needing stronger low bass or substantially higher output, these speakers can be paired with appropriately matched larger speakers, amplification, or a subwoofer.

Key Features

• 3.5-Inch Coaxial Format: Combines woofer and tweeter in a compact full-range speaker assembly.
• 25W RMS Handling: Supports 25 watts of continuous power per speaker.
• Edge-Driven Textile Tweeter: Reproduces high frequencies with a textile dome design.
• Plus One Woofer Cone: Provides increased cone area within the speaker frame.
• 3-Ohm Nominal Impedance: Designed for use with compatible automotive audio systems.
• Compact Mounting Profile: Uses a 3-inch cutout and 1-7/16-inch mounting depth.

Design & Installation

The REF307F uses polypropylene Plus One woofer cones, rubber surrounds, and edge-driven textile tweeters in a two-way coaxial design. Its compact optimized frame is intended to fit standard 3.5-inch vehicle speaker locations. The pair is finished in black and does not include speaker grilles.

Confirm that the vehicle has sufficient clearance for the 3-7/16-inch external diameter, 3-inch mounting cutout, and 1-7/16-inch mounting depth before installation. Observe speaker polarity when connecting the factory wiring or amplifier leads, and match amplifier output conservatively to the 25W RMS-per-speaker rating. The package includes foam mounting tape, but vehicle-specific adapters, wiring harnesses, and mounting hardware may be needed depending on the installation location.