KICKER 51KSC6504 KS Series 6.5" Coaxial Speakers – 4 Speakers / 2 Pairs
Premium KICKER Sound for a Complete 4-Speaker Upgrade
Upgrade your factory audio system with this 4-speaker bundle of Kicker 51KSC6504 KS Series 6.5" coaxial speakers. This package includes two complete pairs (4 speakers total), making it an excellent choice for vehicles that use 6.5" speakers in both the front and rear locations.
KICKER's KS Series is designed for listeners who want a noticeable improvement in sound quality without moving to a complicated component speaker system. Internally dampened polypropylene woofer cones provide accurate midrange and powerful midbass, while 3/4" silk-dome tweeters produce smooth, detailed highs without the harshness often associated with factory speakers.
With up to 100 watts RMS recommended power per speaker, these KS Series speakers perform well with an upgraded head unit and really come alive when paired with a quality aftermarket amplifier.
What's Included
- (2) Pairs Kicker 51KSC6504 KS Series 6.5" Coaxial Speakers
- Speaker grilles
- Factory KICKER packaging and included accessories
Why Choose the KICKER KS Series?
Complete 4-Speaker Upgrade
This bundle gives you four matching KICKER KS Series speakers, making it ideal for upgrading both front and rear factory speaker locations at the same time. Using matching speakers throughout the vehicle helps create consistent sound quality and tonal balance from front to rear.
Premium Silk-Dome Tweeters
Each 51KSC6504 features a 3/4" silk-dome tweeter powered by a neodymium magnet. Silk tweeters are known for producing smooth, natural high frequencies, giving vocals and instruments greater detail without becoming overly bright or harsh.
Strong Midrange & Midbass Performance
Internally dampened polypropylene woofer cones provide accurate reproduction of vocals, instruments, and midbass frequencies. Durable rubber surrounds allow controlled cone movement while providing long-lasting reliability.
High Power Handling
The KSC650 works with 15 to 100 watts RMS of recommended amplifier power per speaker, giving you plenty of flexibility when designing your system.
Run them from a compatible aftermarket radio for a straightforward upgrade, or pair them with a quality 4-channel amplifier to take advantage of their higher performance potential.
Shallow, Factory-Friendly Design
With a top mounting depth of only 1-13/16", the KSC650 is designed to fit a wide range of factory speaker locations. Its low-profile coaxial design also helps maintain clearance behind factory speaker grilles.
Features
- Genuine Kicker 51KSC6504 KS Series speakers
- 2 pairs / 4 speakers total
- 6.5" 2-way coaxial design
- 4-ohm rated impedance
- 15–100 watts RMS recommended power per speaker
- 200 watts peak power handling per speaker
- 400 watts RMS combined recommended maximum for 4 speakers
- 800 watts peak power handling for 4 speakers
- 3/4" silk-dome tweeters
- Neodymium tweeter magnets
- Internally dampened polypropylene woofer cones
- Durable rubber woofer surrounds
- Smooth, detailed high-frequency reproduction
- Strong midrange and midbass performance
- 90 dB sensitivity
- Shallow mounting design
- Excellent upgrade from factory speakers
- Works with aftermarket head units or external amplifiers
- Speaker grilles included
Specifications
| Specification | Kicker 51KSC6504 |
|---|---|
| Speaker Size | 6.5" |
| Speaker Type | 2-Way Coaxial |
| Quantity | 4 Speakers (2 Pairs) |
| Rated Impedance | 4 Ohms |
| Recommended Power | 15–100 Watts RMS Per Speaker |
| Peak Power Handling | 200 Watts Per Speaker |
| Bundle Recommended Maximum | 400 Watts RMS |
| Bundle Peak Power | 800 Watts |
| Sensitivity | 90 dB @ 1W/1m |
| Frequency Response | 43 Hz – 21 kHz |
| Tweeter Size | 3/4" (20mm) |
| Tweeter Material | Silk |
| Tweeter Magnet | Neodymium |
| Woofer Cone | Polypropylene |
| Woofer Surround | Rubber |
| Mounting Hole Diameter | 4-13/16" |
| Top Mounting Depth | 1-13/16" |
| Bottom Mounting Depth | 2-3/16" |
| Tweeter Protrusion | Approx. 1mm |
| Grilles Included | Yes |
Vehicle Fitment
The Kicker 51KSC6504 is designed to fit a wide variety of vehicles using 6.5" factory speaker locations.
Its shallow mounting depth makes it especially useful for factory speaker upgrades where space behind the door panel or factory grille is limited.
Important: A 6.5" factory speaker size does not automatically guarantee direct fitment. Depending on your vehicle, installation may require speaker mounting adapters, wiring harnesses, or other vehicle-specific installation accessories.
Use our vehicle fit guide to verify compatibility with your specific year, make, model, and factory audio system before ordering.
Frequently Asked Questions
How many speakers are included?
This bundle includes 4 Kicker 51KSC6504 speakers total, consisting of two complete pairs.
How much power can these speakers handle?
KICKER recommends 15 to 100 watts RMS per speaker. For all four speakers, that provides up to 400 watts RMS of combined recommended amplifier power.
What is the difference between KICKER KS and CS Series speakers?
The KS Series is KICKER's higher-performance option and is a great choice when sound quality is the priority. The KS Series uses silk-dome tweeters and rubber woofer surrounds for smooth, detailed sound and offers excellent power handling.
The CS Series is an excellent factory replacement, while the KS Series is the better choice for customers looking for a more refined, higher-performance upgrade.
Can I run these speakers from my factory radio?
Depending on the vehicle and factory audio system, they can be used without an aftermarket amplifier. However, the KS Series has significantly more performance potential when supplied with adequate clean power.
Do I need a 400-watt amplifier?
No. The 400-watt figure represents the combined upper end of KICKER's recommended RMS power range for all four speakers. You do not need to supply the full 100 watts RMS to each speaker for them to perform well.
Would a 4-channel amplifier work well with this bundle?
Yes. A quality 4-channel amplifier is an excellent match for this package. Ideally, choose an amplifier that provides clean power within the speakers' recommended 15–100 watts RMS per channel at 4 ohms.
Are these component speakers?
No. The 51KSC6504 is a 2-way coaxial speaker, meaning the woofer and tweeter are integrated into a single speaker assembly. This makes them easier to install than separate component speakers while still providing excellent sound quality.
Are speaker grilles included?
Yes. Speaker grilles are included with the Kicker 51KSC6504.
Pro Audio Center Expert Recommendation
If you're looking for a noticeable step up from basic factory replacement speakers, the Kicker 51KSC6504 KS Series 4-speaker bundle is an excellent choice.
We especially recommend this package for customers upgrading all four factory speakers and planning to use an aftermarket head unit or 4-channel amplifier. The silk-dome tweeters provide a smoother, more refined top end, while the polypropylene woofers and rubber surrounds deliver excellent midrange detail and solid midbass performance.
For the best installation, pair these speakers with the correct vehicle-specific speaker mounting adapters and plug-and-play wiring harnesses whenever available.