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Kicker KSC 670 Coaxial Speakers

Manufacturer: Stillwater Designs, OK, USA
Distributor: Celsus
Typical Selling price: £99.99

In A Nutshell
A sudden quantum leap in quality for the extra slice of cash asked. However, very like the way wine improves dramatically in quality by the time you spend a tenner a bottle (I am told..) You get an amazingly better result, way more than that the extra spend might suggest. These sound amazing, although I would feed them at least 50 watts RMS if you can. Sweet, crisp, fast silk dome tweeters with neodymium magnets, backed up with a chunky motor underneath that wears some serious heavy-metal top and bottom plates. Kicker’s legendary skill with bass in small spaces is clearly at work here. Because the KSC670 coaxials absolutely rock. Absurd bass for such small speakers, yet with control, clarity and a delicious fidelity that is punching way above their weight. Enormously enjoyable, I was genuinely surprised at how good they were for the money.

Overall 9.0
Sound Quality 9
Build Quality 8
Power 9
Efficiency 9
Value For Money 10

Recommended within Talk Stuff’s audio genre

Editor Review : Kicker KSC670 Coaxial Speakers
The fourth review in a series of seven loudspeakers from one UK supplier. All 6.5 inches or 6.75 inches, fitting in the same hole. How do they vary? Why they different? This is the third pair of loudspeakers from Stillwater Designs of Oklahoma USA’s Kicker brand, having first tried a set of £40 MTX Terminators. The DSC series ones were £50 less a penny, the CSC ones, in the identical chassis and tweeter but with different motors in their guts for more bass, were £70 less a cent.

In the video I made, unboxing and all too brief demonstrating the CSC674, it is all too clear that I am confused if not stupid. It took a little while for it to dawn upon me what that extra £10 was about. After all, while I was taking the products from the carton, I had not yet auditioned them. There is a rare cut edit and I am laughing at myself… However, these KSC 6704 are penny less than £100. So what do you get for thirty quid more?

For a start you get a 20mm soft silk dome tweeter, still with that fancy neodymium magnet, but much more surface area than the 13mm model found on the aforementioned cheaper speakers. Those are engineered to be flush to the surface and very easy to install underneath the factory grills. With these you really want to be using a slightly protruding grill and ideally the ones they came with because they are a much chunkier transducer. If you check out the video below, you will see that I do spot the rather more lavish and expensive amounts of steel, by way of pole plates on the magnet assembly. At time of writing I have not edited the video but I do seem to recall saying something about the likelihood of deeper bass.

You may be surprised but even after all these years I still feel nervous as to whether I can tell these products apart! I need to not have been because the significant extra spend gets you from the realm of a bloody good replacement for the factory rubbish, to the zone of, “bloody hell they sound fabulous where did you get those mate?” From your passengers! Because I can tell you that these loudspeakers sound at least as good as ones that would have cost double the price five years ago. First off, although clearly wound to a low impedance so as to be very vigorous, that silk dome tweeter is bonkers posh for a hundred quid. I was immediately comparing it to crazy end HIFI in thinking that it might be a trifle strident. But it was articulate, very bloody fast and you could tell that it reaches up beyond 20 kHz. It could just do those delicious breathy and tinkly sounds. And then the bit that made my jaw drop.

The ridiculous, stupefying accurate bass end.

I don't think anybody told Kicker that you cannot make that much bass from a 6.75 inch speaker. I have tested A LOT of automotive speakers in my time. I have even tested loudspeakers this size that claimed to be miniature subwoofers. Yes this set of £100 coaxials from Stillwater Designs sounded so fabulous and rich and deep that I have issues. At this point there is only one other conclusion. The Morel four channel amplifier that I am using as reference must have something to do with it. Instead of overloading the little cones until they clatter or crack the amplifier is keeping control. Plus the loudspeaker is bloody phenomenal to be able to do what it does. I'm accusing this loudspeaker of being able to review amplifiers with!

I played some tracks from an especially high-quality, SACD-equipped yet ancient deck from Sony, that had been a giveaway from KEF for their 50th birthday celebrations. I listened to, Daft Punk’s “Get Lucky” and “Royals” by Lorde, amongst others. The four channel Morel amplifier, bridged was feeding a solid 70 Watts RMS to each loudspeaker, with what is obviously still proper headroom.

In my neat demonstration enclosures, surrounded by the scruffy wiring that gathers dust and tests my saintly wife's patience, (since I never put it away!) once more I had high quality sound playing on the landing.

I stood there and marvelled at them gently for a moment, taking in just how holosonic the damn things were. A lovely rich soundstage, seemingly coming from beyond the enclosures, even beyond the wall in front of me, which pinch hits acoustically, for the car’s windscreen in test rig terms. Yes those tweeters were a little hectic for pure on-axis listening but they do not swivel upon their pole mounts and so are absolutely designed for you to listen to them off axis. But to the bottom end was ridiculous. Not just rich and deep, and I mean exactly as if there was a small cubic subwoofer involved somewhere, but with a amazing control. Even given that that Morel amp is looking like a delicious reference piece, the wobbly variation in the bass notes underneath Lorde singing about not being Royal was a ruddy revelation. I enjoyed them so much.

Yes, £100 is the first unit of “Oer that's proper money!” And while the previous four products are in the same price bracket as many of us may splurge on a meal out, as in very affordable, it’s these or a £50-a-head meal for two and that means hearing them and being bloody certain before you spend, or else seeking a review.

In my opinion and speaking as a fat bloke, I would spend the money on the speakers.


Speaker System: 2-way coaxial
Tweeter: 20mm Balanced Silk Dome, Neodymium magnet
Woofer: Injected Polypropylene cone with rubber surround
Woofer Mounting Depth: 50mm
Rated Input Power: 100W
Peak Input Power: 200W
Sensitivity: 90dB/W/m
Frequency Response: 40Hz to 21,000Hz