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Infinity Primus 503F
Upgrade Your Vehicle With Confidence. This Is Built to Fit, Perform, and Last
Real installer support before and after purchase
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Ships within 1-3 days
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Infinity Primus 503F 5.25" 2-Way Coaxial Car Speakers
Product Overview:
The Infinity Primus 503F is a 5-1/4" coaxial speaker designed as a direct high-fidelity upgrade for factory car audio systems. Part of the refreshed Primus line, these speakers focus on compact fitment, high sensitivity, and the signature "lifelike" sound Infinity is known for. They are particularly effective in vehicles with low-power factory head units that need a boost in clarity and volume.
Key Features
Plus One™ Woofer Cones
Infinity uses its patented Plus One™ polypropylene cones, which extend the cone surface area closer to the edge of the basket. This provides up to 35% more radiating surface area than other speakers in the same size class, resulting in deeper bass response and higher efficiency without needing a larger mounting hole.
Edge-Driven Silk Dome Tweeters
Unlike cheaper balanced-dome tweeters, the 503F features edge-driven silk dome tweeters. This design provides a broader high-frequency dispersion and smoother response, ensuring that vocals and high-frequency details remain crisp and natural even at high volume levels.
True 4-Ohm Architecture
These speakers utilize a 3-ohm low-impedance voice coil. This design is engineered to compensate for the high resistance found in thin factory speaker wiring, allowing your head unit or amplifier to deliver more power. This "true 4-ohm" setup safely extracts every watt possible for a stronger, clearer sound.
Vented Basket Design
The super-rigid vented basket does more than just look sleek; it acts like a fan to wick heat away from the motor structure as the cone moves. This cooling effect results in lower distortion at high output levels and increases the overall longevity of the speaker components.
Technical Specifications
| Category | Specification |
| Performance | |
| Speaker Size | 5-1/4" (130mm) |
| Power Handling | 40W RMS / 120W Peak |
| Nominal Impedance | 3.0 Ohms |
| Frequency Response | 75Hz – 20kHz |
| Sensitivity (2.83V@1m) | 91 dB |
| Construction | |
| Woofer Material | Polypropylene with Rubber Surround |
| Tweeter Material | Edge-driven Silk Dome |
| Crossover Point | 6kHz @ 6dB/octave |
| Dimensions | |
| Mounting Depth | 1-13/16" |
| Cutout Diameter | 5-1/8" |
- Ships within 1–3 business days from our warehouse
- Tracking included with every order
- Free 30-day returns if it doesn’t work for your setup
- 2-year manufacturer warranty
- Authorized dealer guarantee
- Real installer-backed support before and after purchase
Infinity Primus 503F
Sale price$69.95
Why This Upgrade Makes Daily Driving Better
Ease of Use & Safety
Hands-free control reduces distraction and frustrationwhile driving.
Expandable by Design
Add backup cameras, better speakers, amps, or subsanytime.
FITMENT & INSTALLATION MADE SIMPLE
WHAT VEHICLES IT WORKS WITH
FIND THE RIGHT PRODUCT FOR YOUR EXACT VEHICLE
We verify compatibility before you buy, no guesswork.
DIY FRIENDLY IF:
- You're comfortable with basic tools
- You follow provided instructions
PROFESSIONAL INSTALL RECOMMENDED IF:
- Your vehicle requires dash kits or wiring adapters
- You want a turnkey experience
INSTALLATION CREDIT & SUPPORT:
- $75 Installation Credit when purchased online
- Speak to real installers before you buy
- Bring it into one of our locations for install
40 Years of Installation Experience
Tens of Thousands of Installs Completed
Authorized Dealer Full Warranties
Why Buying This Here Is Safer Than Anywhere Else
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Verified Vehicle Fit
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Authorized Products
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Easy Returns
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Physical stores & real installers
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FREQUENTLY ASKED QUESTIONS
FREQUENTLY ASKED QUESTIONS
How do I know this stereo or speaker will fit my car?
Select your year, make, and model using the Vehicle Fit Guide at the top of the page. You’ll only see products that are compatible with your exact vehicle setup.
What happens if I order something that doesn’t fit?
You can return or exchange it within 30 days. We’ll help you identify the correct part for your vehicle so you don’t have to guess again.
Are these products brand new and covered by warranty?
Yes — all products are brand new, authentic, and sold as an authorized dealer, which means they include a full manufacturer warranty.
Can you install this for me, or do I need to do it myself?
You can do either. Install it yourself, or use your $75 installation credit at our shop and have it professionally installed by our team.
What if I don’t know what to choose for my car?
Tell us your vehicle and what you want to improve (sound, bass, CarPlay, etc.). We’ll recommend the exact products that fit your car and your budget.
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