INFINITY ALPHA 603 - New Gen Alpha Series 6.5″ 2-Way Coaxial Speakers

INFINITY ALPHA 603 | 6.5″ 2-Way Coaxial Speaker System | 60 W RMS | 90 dB SPL

The Infinity Alpha 603 is a 6.5″ (165 mm) 2-way coaxial car speaker system crafted for drivers who want more musical detail and impact from their factory stereo setup. Featuring Infinity’s patented Plus One™ woofer cone and a high-output PEI balanced dome tweeter, this system delivers clear, immersive sound with enhanced bass and accurate highs—ideal for use as a full-range upgrade in front or rear locations.

Designed with Infinity’s competitively tuned sound signature, the Alpha 603 delivers consistent tonal balance across the frequency spectrum, making it an ideal match for both stock and aftermarket head units. With 60 W RMS (480 W peak) power handling and a broad 55 Hz–20 kHz frequency response, this speaker provides headroom and dynamic range typically found in higher-end systems—all while maintaining easy installation and 4 Ω compatibility.

Engineered for both clarity and affordability, the Infinity Alpha 603 is perfect for anyone looking to upgrade their car's audio system with a dependable, great-sounding coaxial solution backed by Infinity’s legacy of innovation.

Tech Specs

Model: Infinity Alpha 603

Type: 2-Way Coaxial Speaker System

Woofer: 6-1/2″ (165mm) Plus One™ woofer cone

Tweeter: PEI balanced dome tweeter

Power: 60 W RMS, 480 W peak

Sensitivity: 90 dB (@2.83V)

Impedance: 4 Ω nominal

Frequency Response: 55 Hz – 20 kHz

Applications: OEM replacement or upgrade for factory coaxial speaker locations; suitable for both front and rear installations

Key Highlights

Plus One™ Woofer Cone Architecture: Increases cone surface area for stronger bass output and better low-frequency performance than similarly sized speakers.

PEI Balanced Dome Tweeter: Delivers crisp, non-fatiguing high frequencies at all listening levels—ideal for long drives or daily commutes.

Competitively Tuned Sound: Each Alpha series speaker is voiced against leading competitors to ensure balanced response and consistent Infinity performance.

Durable and Efficient: Designed to perform reliably with factory or aftermarket head units without requiring external amplification.

Factory-Friendly Fit: The coaxial design simplifies installation with a single integrated unit, ideal for quick upgrades with minimal modifications.