INFINITY ALPHA 603M - New Gen Alpha Series 6.5″ 3-Way Coaxial Speakers

Infinity Alpha 603M | 6.5″ 3-Way Car Speaker System | 60 W RMS | 90 dB SPL

The Infinity Alpha 603M is a high-performance 6.5″ three-way car speaker system designed to deliver crisp highs, dynamic mids, and punchy bass with broad frequency response and high efficiency. Its advanced Plus One™ woofer cone architecture and edge-driven silk dome tweeter enable rich, distortion-free audio across the spectrum—making it ideal for audiophiles seeking a compelling factory upgrade or custom install.

With 60 W RMS (480 W peak) power handling, a 4 Ω impedance, and 90 dB sensitivity (@2.83V), the Alpha 603M delivers excellent output and clarity even when powered by standard head units. Engineered for clarity and durability, it combines premium materials like PEI dome tweeters with Infinity's proprietary sound-tuning, making it a competitively priced, high-value solution for everyday driving soundscapes.

Product Highlights:

6.5″ (165 mm) three-way car speaker system with grille for full-range sound

Plus One™ woofer cone architecture for increased cone area and bass response

Edge-driven silk dome tweeter for smooth, extended highs without harshness

PEI balanced dome tweeter for crystal-clear treble even at high output levels

High 90 dB sensitivity for strong output from factory or aftermarket head units

Tuned for consistent Infinity sound signature—powerful yet refined

Tech Specs:

Model: Alpha 603M

Type: 3-Way Coaxial Car Speaker System

Woofer: 165 mm (6.5″) Plus One™ polypropylene cone

Tweeter: Edge-driven silk dome tweeter + PEI balanced dome tweeter

Power: 60 W RMS / 480 W peak

Sensitivity: 90 dB (@2.83V)

Impedance: 4 Ω

Frequency Response: 55 Hz – 20 kHz

Applications: Front or rear factory replacement, custom installs, OEM upgrades, compatible with stock or amplified systems

Engineered by HARMAN, Tuned by Infinity

With patented innovations like the Plus One™ cone and the use of premium soft-dome tweeters, Infinity Alpha speakers are tuned to outperform the competition in both clarity and impact. Backed by decades of acoustic research from HARMAN, the Alpha 603M offers an affordable path to audiophile-grade performance, competitively engineered for balanced sound that’s never harsh—just honest.