Infinity Kappa 120.9w 12 Inch DVC Subwoofer

Product Details
Manufacturer: Infinity
Website: http://www.jblcaraudio.co.uk
Typical Selling price: (CAS) £112.49

Good looking dual voice coil subwoofer with a switch to enable use at four or two ohm impedance to better load an amplifier. The cone is coated fibreglass and is very rigid, with a raised dust dome and shiny collar detail with the Kappa branding. The weighty magnet has a rubber boot around it and the magnet centre decal has a clear plastic over it, that is peeled off when the installation is finished for better cosmetics when used in boxes with clear windows.

The two voice coils are terminated at a single set of crimp terminals, operated by 3mm Allen (hexagon) wrench, with a switch that is slightly confusing as the housing is see through and it is only upon reading the manual that it becomes clear that the switch’s labels appertain to the number left exposed, not the side the switch has been slid to, clearly visible, see-through.

Supplied with that Allen key, some sticky back foam strip speaker gasketing, a multi-language manual with truly excellent information about bass in cars and the sorts of enclosures you can use and a technical sheet showing graphs for different impedance use and in-car with transfer function included and also as an out-of-car or more anechoic response curve.

The test rig comprised a JBL GTO 24001 bass amp, Alpine MRX-F30 four channel amplifier, some Fusion CP-FR6930 ovals and a pair of Alpine DDLinear DDL RT17S components. All driven by a Kenwood KDC-9537U single-DIN CD tuner, on an Odyssey battery with StreetWires power cables to 1/0 Gauge and JL Audio RCA interconnects and some fork truck cable-break connectors for safety. The subwoofer was in a sealed Acoustic Wood enclosure of marine ply.



- Frequency response: 23Hz to 400Hz
- Power Handling: 350w RMS (1.4kw max)
- Coated woven glass fibre cone with shiny branded trim ring
- Die cast Aluminium chassis with air venting
- Large rubber top roll suspension
- Selectable Smart Impedance system (SSI) means 2 or 4 Ohm switchable
- SSI terminals, Allen-headed grub screw with impedance switch
- Voice Coil Diameter: two 2 inch (51mm)
- Mounting depth 160mm
- Magnet has Aluminium heatsink and rubber boot, clear decal-cover over rear end is removed upon installation
- Efficiency: 91dB 1w/1M
-Xmax 17.5mm
- Fms: 27.2Hz
- Qes: 0.51 @ 2 Ohms, 0.52 @ 4 Ohms
- Qms: 4.38 @ 2 Ohms, 2.47 @ 4 Ohms
- Qts: 0.46 @ 2 Ohms, 0.43 @ 4 Ohms
- Vas: 54.43 Litres


Editor Review : Infinity Kappa 120.9w 12 inch Dual Voice Coil Subwoofer

This is a subwoofer for those well on the way to finally satisfying their bass hunger. This is not a huge amount of money compared to the weapons-grade woofers around but it ain’t cheap. There are a lot of woofers out there for less money and some of them will claim to be able to handle more watts, too.

But this is a slice of engineering. One so sexy you might want to put its rear end on display, or else have its butt visible through a window in a bandpass box, so Infinity have a layer of clear polythene over the surface of the magnet’s rear decal and the idea is that you peel this off last of all upon installation, so it looks pristine.

The chassis is massive and black texture-coated and there’s a ring of casting below the cone, which turns out to be the heat sinking for a serious pair of voice coils. They are switchable so as to offer either 4 Ohms or 2 Ohms load to the amplifier you want to use. As long as the output of your bass amp channels isn’t above the RMS abilities of the sub, you’ll be OK.

But I had a ridiculous amplifier, which even at less than well supported conditions - with no alternator feeding the system as it runs, will be more than able to raise a kilowatt. So let’s see what it sounds like…

OK, I ran it at 4 Ohms and was still able to push it to the point where I could see it didn’t like it, so the power/impedance issue was not part of the reckoning. At first, I was fretty and worried as I just didn’t like it one bit. Then I realised I had the settings badly arranged and had a good tweak, turning the ovals all but off as their bass was so strong, it was occluding my testing efforts. Then I wicked back the DDLinear Alpines and had a good play with the bass amps settings.

Again, I was worried. I could hear this chattering, as though the speaker was buzzing, at all volumes, from loud to soft. Then it dawned upon me that the seal on my box might be suspect, so I caulked it all to hell with wasteful amounts of insulation tape rammed up the edge where it meets the box and you know what? Cured! Just goes to show and of course utterly vindicates why Infinity see fit to supply you with some foam speaker gasket. Embarrassing.

It soon became clear that the woofer’s spandy fresh new suspension was as stiff as a virgin’s willy at a car show and in fact as the test went on, it became just a tiny bit more wobbly or compliant. And come to think of it, although it was a while ago, when it was delivered, I was told it aughta be spanked and run in well before any judgements are passed.

Nonetheless, buyers will also judge in their first few hours of ownership. I played mad bass CD material down the system and a panoply of increasingly familiar bonkers bass tests. But then did something I haven’t in a long while. I pulled out my Focal Spirit of Sound #6 CD. The original - and tried out the track that shows off the Morel Ultimo sub’s incredible ability to stop and start off so well.

I worked out in the end, that even after some real running in, the basic quality of the woofer was showing through and that it was remarkable. For so very much less than a Morel, you are getting a slice of that same quality of sound.

The cone is glass, not carbon, so weighs a bit more and the coil assembly, while serious, isn’t as bonkers as the five inch job on the six hundred quid woofer I’m warbling on about but the point is, the sound was tight, accurate and able to really drop and wobble down.

In fact way deeper than said paragon woofer-of-comparison can do. So it’s not an all out bass heads’ tool but more a powerful all rounder that can be set to a damn good impersonation of high SQ as well as being able to spank you a bit harder when you want to impress your mates.

All in all, a very cool piece of kit and one that for the cash, goes a good eight points of the way to ten in VFM as well as scoring good and high on the Sound Quality front as well. Not desperately efficient in use but that had to give in the face of the high power handling and the top end output.

Easily recommended.





In a Nutshell
A good looking and well built woofer, able to take some muscle and deal out some bass, not just all the way down to the silly Bass CD lows but also with a real slice of high SQ as well. So not cheap but still good VFM



Overall 8.8
Sound Quality 9
Build Quality 10
Power Handling 9
Efficiency 8
Value For Money 8