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The Kicker 51KSS6704 is a KS Series 6.75" (165 mm) 2-way component speaker system rated at 125W RMS, featuring 1" silk-dome tweeters and the option to run as a high-end coaxial setup.
Other sizes in the KS Series 2-way component range: the 5.25" KSS504, 6.5" KSS6504 and 6x9" KSS6904.
Key specifications
- Woofer: 6.75" (165 mm) polypropylene
- Tweeter: 1" (25 mm) silk dome
- Power: 125W RMS, 250W peak
- Recommended power: 15–125W
- Impedance: 4 ohms
- Sensitivity: 91 dB (1W/1m)
- Frequency response: 35Hz–21kHz
- Woofer mounting: 141 mm hole, 46 mm depth
- Crossover: 12dB high-pass at 4,000Hz, tweeter attenuation 0/4.5/9dB
KS Series 6.75" component speaker system
KS Series speakers are designed to deliver concert-like volume without losing smoothness or detail. Internally dampened polypropylene cones and rubber surrounds handle precise midrange and bass, while silk-dome tweeters produce natural, detailed highs.
Run them as a traditional component system with separate tweeters, or convert to a high-end coaxial setup. The woofer's removable bullet-style phase plug is replaced with a special adapter, letting the 25 mm silk-dome tweeters rotate and tilt for improved off-axis performance and greater flexibility in system design.
Features
- High power handling — 125W RMS, 250W peak
- Silk-dome tweeters for smooth, detailed highs
- Polypropylene woofer cone with rubber surround
- Thin-mount design fits behind factory grilles
- Four tweeter mounting options
- Articulating tweeter pod included
- Compact crossover for easier mounting
- Grilles included
Explore the full range in Kicker KS Series Speakers.
Specification
| Speaker Size (in) | 6.75" |
|---|---|
| Style | Component |
| Impedance | (Ohms) 4 |
| RMS Power (W) | 125 |
| Peak Power (W) | 250 |
| Sensitivity | (dB @ 1W/1m) 91 |
| Frequency Response | (Hz) 35-21k |
| Depth (cm) | 4.6 |
| Woofer Mounting Hole Diameter [in, mm] | 5-9/16 , 141 |
| Woofer Bottom Mount Depth [in, mm] | 1-13/16 , 46 |
| Flush Mount Tweeter Depth [in,mm] | 11/16 , 17 |
| High Pass [dB], at Frequency [Hz] | 12, 4,000 |
| Low Pass [dB], at Frequency [Hz] | none |
| High Frequency Output Attenuation [dB] | 0, 4.5, 9 |
More specs
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What's Included
- Kicker 51KSS6704
Kicker
About the Kicker 51KSS6704
From our tech experts at CEN
A 6.75 inch component set, with separate tweeters that can be mounted higher up where you will actually hear them, rated at 125w RMS.
Who it suits
Drivers who want the best result from a door upgrade and are happy for tweeters to be mounted separately, which usually means a professional fit.
Our tech experts advise
Speaker sizes, adapter rings and harnesses vary by vehicle, year and trim, so we confirm what your car takes before ordering rather than guessing. Treating the door skin matters as much as the speaker: a good driver in an untreated door is doing half a job. Installation is priced per vehicle, so get in touch with your make, model and year and we will confirm what it needs. See car audio installation.
Explore the full Kicker range at CEN, with fast UK dispatch and expert advice from our Nottingham team. Shop all Kicker
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Frequently Asked Questions
Q: Will these speakers fit my car?
A: Most car speakers are standard sizes, but mounting depth and fitting rings vary by vehicle. Check the size in the Specification tab against your vehicle, or contact CEN with your registration and we will confirm fitment and any adapters or fitting kits you need.
Q: Do I need an amplifier to run these speakers?
A: Not always. Most speakers will run from a standard head unit, but a dedicated amplifier lets them perform at their best, particularly for component sets and higher power handling models. The RMS figure in the Specification tab is the guide to how much clean power they can use.
Q: What is the difference between coaxial and component speakers?
A: Coaxial speakers combine the tweeter and woofer in one unit for a simple like-for-like upgrade. Component sets separate the tweeter and woofer with a crossover for better imaging and detail, and suit installs where sound quality is the priority.
Q: Do these come as a pair?
A: Unless stated otherwise, car speakers are sold in pairs. Check the product title and What's Included tab, which lists exactly what is in the box.
Q: Can CEN fit these speakers for me?
A: Yes. CEN offers professional installation from our Nottingham premises. Contact us to book an installation slot or ask for a fitting quote.
Q: How much power does the Kicker KSS6704 handle?
A: It is rated at 125 watts RMS and 250 watts peak at 4 ohms, and works best with 15 to 125 watts of recommended power.
Q: What size hole does the KSS6704 woofer need?
A: A 141 mm mounting hole, with a woofer bottom mount depth of 46 mm.
Q: Can the KSS6704 tweeters be flush mounted?
A: Yes. Flush mounting needs a 45 mm hole and 17 mm of depth. Four tweeter mounting options are available, including an articulating pod.






































