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The Kicker 51KSS504 is a KS Series 5.25" (130 mm) 2-way component speaker system rated at 100W RMS, featuring 1" silk-dome tweeters and the option to run as a high-end coaxial setup.
The KS 2-way component range is also available in 6.5" (KSS6504), 6.75" (KSS6704) and 6x9" (KSS6904).
Key specifications
- Woofer: 5.25" (130 mm) polypropylene
- Tweeter: 1" (25 mm) silk dome
- Power: 100W RMS, 200W peak
- Impedance: 4 ohms
- Sensitivity: 88 dB (1W/1m)
- Frequency response: 38Hz–21kHz
- Woofer mounting: 115 mm hole, 45 mm depth
- Crossover: 12dB high-pass at 4,000Hz, tweeter attenuation 0/4.5/9dB
KS 5.25" (130 mm) Component Speaker System
51KSS504
KS Series speakers are designed to play at high volume while retaining smoothness across the frequency range. Internally dampened polypropylene cones and rubber surrounds deliver precise midrange and bass. Silk-dome tweeters handle the highs with natural detail.
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 better off-axis performance and more flexible installation. Recommended power: 15–100W RMS.
Features
- High power handling — 100W RMS, 200W peak
- Silk-dome tweeters for smooth, detailed highs
- Polypropylene 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
| Woofer Size (in) | 5.25" |
|---|---|
| Tweeter Size (in) | 1" |
| Style | Component |
| Dome Material | Silk |
| Impedance | (Ohms) 4 |
| RMS Power (W) | 100 |
| Peak Power (W) | 200 |
| Sensitivity | (dB @ 1W/1m) 88 |
| Frequency Response | (Hz) 38-21k |
| Depth (cm) | 4.5 |
| Mounting Hole Diameter (cm) | 11.5 |
| Woofer Mounting Hole Diameter [in, mm] | 4.5, 115 |
| Woofer Bottom Mount Depth [in, mm] | 1.75, 45 |
| 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 51KSS504
Kicker
About the Kicker 51KSS504
From our tech experts at CEN
A 5.25 inch component set, with separate tweeters that can be mounted higher up where you will actually hear them, rated at 100w 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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More options from the same range, in stock and ready to go
Best SellerKicker 51KSC4604 KS Series 4x6" 2 Way Car Door Dash Shelf Coaxial Speakers 75w RMS
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Kicker 51KSC69304 KS Series 6x9" 3 Way Parcel Shelf Triaxial Speakers 150w RMS
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Kicker 51KSC6704 KS Series 6.75" 17cm 2 Way Car Door Coaxial Speakers 100w RMS
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Kicker 51KSC2704 KS Series 2.75" 7cm Car Door Dash Mid/Tweeter Speakers 50w RMS
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Kicker 51KST2504 1" Silk Dome Tweeters 75w RMS Pair
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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: Can the Kicker KSS504 be used as a coaxial speaker?
A: Yes. The woofer's removable phase plug is replaced with an adapter so the 25 mm tweeter can sit on the woofer, rotate and tilt, giving a high-end coaxial setup.
Q: How much power does the KSS504 handle?
A: It is rated at 100 watts RMS and 200 watts peak at 4 ohms, and works best with 15 to 100 watts of recommended power.
Q: What size hole do the KSS504 tweeters need for flush mounting?
A: A 45 mm hole, with a flush mount depth of 17 mm.
