INFINITY ALPHA 603C | 6.5″ 2-Way Component Speaker System

The Infinity Alpha 603C is a precision-engineered 6.5″ two-way component speaker system designed for clean, dynamic sound in upgraded car audio installations. Featuring Infinity’s exclusive Plus One™ woofer cone architecture and a smooth, edge-driven silk dome tweeter, this set delivers extended bass and crisp, detailed highs—ideal for front-stage clarity in both OEM replacements and custom systems. With high power handling of 90 W RMS (720 W peak) and a wide frequency response, the Alpha 603C offers impactful performance even at higher volumes, while its 4 Ω nominal impedance ensures compatibility with a wide range of aftermarket amplifiers and head units.

The component design separates the mid-woofer and tweeter, allowing optimal placement for superior imaging and staging. Paired with Infinity’s competitively tuned sound signature, the Alpha 603C is purpose-built for discerning listeners seeking a more refined, musical experience—without the premium price tag. Rugged, stylish, and engineered with Infinity’s new ID design language, this system is a perfect match for enthusiasts who demand more than factory sound.

Tech Specs

Model: Infinity Alpha 603C

Type: 2-Way Component Speaker System

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

Tweeter: Edge-driven silk dome tweeter

Power: 90 W RMS, 720 W peak

Sensitivity: 90 dB (@2.83V)

Impedance: 4 Ω nominal

Frequency Response: 60 Hz – 20 kHz

Applications: Front-stage upgrade for OEM or aftermarket audio systems; ideal for amplified or high-power head units

Key Highlights

Plus One™ Cone Technology: Patented woofer design provides more cone surface area than standard speakers for deeper bass and improved efficiency.

Edge-Driven Silk Dome Tweeter: Unlike common w-dome tweeters, the Alpha 603C's silk dome is edge-driven for smoother frequency response and cleaner highs at all volume levels.

New Infinity ID Design: Updated aesthetics and materials appeal to audio enthusiasts looking for modern styling with acoustic performance.

Competitively Tuned: Tuned against class competitors to ensure balanced output and a consistent Infinity sonic signature.

Value Engineered: Designed to deliver Infinity sound at an affordable price, without compromising on materials or quality.

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.

INFINITY ALPHA 603 | 6.5″ 2-Way Coaxial Speaker System

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.

INFINITY ALPHA 693M | 6x9″ 3-Way Coaxial Speaker System

The Infinity Alpha 693M is a robust 6x9″ 3-way coaxial speaker system built to deliver exceptional clarity, volume, and dynamic range for car audio enthusiasts looking to elevate their sound experience. Engineered with Infinity’s patented Plus One™ woofer cone architecture, the Alpha 693M produces deeper, more resonant bass, while its dedicated midrange driver and PEI balanced dome tweeter ensure rich vocal clarity and detailed highs. The three-way configuration makes this speaker ideal for rear deck or door placements where full-spectrum sound and staging matter most.

With an upgraded power handling of 65 W RMS (195 W peak) and a high-efficiency 93 dB sensitivity rating, the Alpha 693M can deliver substantial volume with minimal power—perfect for use with factory head units or aftermarket amps. The 3.0-ohm impedance allows it to pull more power safely from modern amplifiers, maximizing output and headroom. Paired with Infinity’s competitively tuned sound signature, this speaker ensures vibrant, musical performance across all genres.

Designed to meet the demands of modern car audio systems, the Infinity Alpha 693M blends high output, tonal accuracy, and rugged build quality into a versatile 6x9″ solution.

Tech Specs

Model: Infinity Alpha 693M

Type: 3-Way Coaxial Speaker System

Woofer: 6x9″ (152x230mm) Plus One™ woofer cone

Tweeter: PEI balanced dome tweeter

Power: 65 W RMS, 195 W peak

Sensitivity: 93 dB (@2.83V)

Impedance: 3.0 Ω nominal

Frequency Response: 45 Hz – 20 kHz

Installation Diameter: Not officially specified

Mounting Depth: Not officially specified

Basket Depth: Not officially specified

Weight: Not officially specified

Applications: Rear deck or rear door upgrade for full-range sound; compatible with both stock and amplified systems

Key Highlights

Three-Way Design: Offers dedicated drivers for bass, midrange, and highs—providing greater separation and clarity.

Plus One™ Woofer Cone: Patented technology increases cone surface area for stronger, deeper bass response.

High Sensitivity (93 dB): Optimized for loud, clear playback even with limited amplifier power.

3.0-Ohm Impedance: Designed to extract more usable power from today’s head units and amplifiers.

Competitively Tuned by Infinity: Voiced to deliver a balanced, musical performance that exceeds typical factory and aftermarket options.

The Infinity Alpha 403F is a compact yet powerful 4″ coaxial car speaker system, expertly engineered for clean mids and sparkling highs in space-constrained applications. Its advanced Plus One™ woofer cone architecture and PEI balanced dome tweeter deliver rich, full-spectrum sound with minimal distortion—perfect for upgrading stock systems in smaller doors, dashboards, or rear factory locations.

With 40 W RMS (320 W peak) power handling, a 4 Ω nominal impedance, and 88 dB sensitivity (@2.83V), the Alpha 403F is optimized for strong output from both stock and aftermarket head units. Designed to bring Infinity’s signature sound to tighter installation environments, this speaker delivers surprisingly full-bodied audio in a highly space-efficient format.

Product Highlights:

4″ (100 mm) coaxial car speaker system optimized for compact locations

Plus One™ polypropylene woofer cone for increased cone area and better bass

PEI balanced dome tweeter for crisp, detailed treble with low distortion

High-efficiency 88 dB sensitivity ideal for use with factory or low-power systems

Smooth frequency response from 80 Hz to 20 kHz for a natural listening experience

Easy-fit design for factory replacements or custom compact installs

Tech Specs:

Model: Alpha 403F

Type: 2-Way Coaxial Car Speaker System

Woofer: 100 mm (4″) Plus One™ polypropylene cone

Tweeter: PEI balanced dome tweeter

Power: 40 W RMS / 320 W peak

Sensitivity: 88 dB (@2.83V)

Impedance: 4 Ω

Frequency Response: 80 Hz – 20 kHz

Applications: Dash, door, or rear fill in compact vehicles; OEM upgrade or retrofit where space is limited

Infinity Quality in a Compact Form

Like the rest of the Alpha series, the 403F features Infinity’s acclaimed sound engineering and tuning, with performance that punches above its size. Whether you’re enhancing your vehicle’s factory system or building a discreet custom install, the Alpha 403F ensures clean, balanced audio—Infinity sound, scaled down, but never compromised