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Infinity 120.9w

Kappa Series 12" subwoofer with selectable 2- or 4-ohm impedance

Item # 1081209W

Infinity Kappa subwoofers combine great-sounding bass with the wiring versatility you need to build a system that...

Infinity Kappa subwoofers combine great-sounding bass with the wiring versatility you need to build a system that...

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Discontinued item
6 questions - 7 answers

Item # 1081209W

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About the Infinity 120.9w

Infinity Kappa subwoofers combine great-sounding bass with the wiring versatility you need to build a system that can expand to meet your changing needs. And these enhanced woofers feature superior construction that makes the thump come easy.

Infinity Kappa subwoofers combine great-sounding bass with the wiring versatility you need to build a system that can expand to meet your changing needs. And these enhanced woofers feature superior construction that makes the thump come easy.

The Kappa 120.9w 12" subwoofer features Infinity's unique Selectable Smart Impedance design, which lets you build exactly the system you want — high-power or multi-sub — without complicated wiring. Just flip the convenient impedance switch to safely choose between 2 or 4 ohms. If you're thinking about upgrading your amplifier or adding another sub down the line, this sub makes it easy to reconfigure — and it's nearly impossible to wire incorrectly.

This sub handles plenty of power and sounds great in sealed and ported enclosures, too. The coated glass-fiber cone offers remarkable rigidity that minimizes distortion, while the thick rubber surround promotes smooth excursion. Add the hefty cast aluminum basket to the mix and you've got proven delivery system for potent low end.

Priced per speaker

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Product highlights:

  • 12" subwoofer with selectable 2- or 4-ohm impedance
  • coated glass-fiber cone with rubber surround
  • cast aluminum basket
  • frequency response: 23-400 Hz
  • power range: 50-350 watts RMS (1,400 watts peak power)
  • sensitivity: 91 dB
  • top-mount depth: 6-3/8"
  • sealed box volume: 1.0 cu. ft.
  • ported box volume: 2.0 cu. ft.
  • warranty: 3 years
  • Our 60-day money-back guarantee
  • MFR # 120.9W

What's in the box:

  • One 12" Woofer
  • Self-adhesive foam gasket
  • 3mm Allen wrench
  • Owner's manual (English/ French/ Spanish/ eleven other languages)
  • Technical data sheet
  • Warranty and on-line product registration information

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Product Research

Features
Enclosure Compatibility
Specifications

Features

Selectable Impedance: For increased system flexibility, the woofer impedance is switchable. There is a 2 ohm/4ohm switch above the wire terminals, this provides easy configuration of the voice coil. The power handling is the same for either setting; 350 watts RMS/1400 watts peak.

Woven Glass-Fiber Cone: The cone material is extremely stiff, minimizing cone flex; this results in very low distortion and improved clarity.

Vented Polepiece: Venting the polepiece reduces air compression under the dustcap which minimizes mechanical noise and provides more constant mechanical Q for reduced distortion.

Terminal: The set screw wire terminals will accept bare wire up to 8 gauge.

Enclosure Compatibility

Sealed Box: Infinity recommends a sealed enclosure with an internal volume of 1.0 cu/ft.

Ported Box: Infinity recommends a ported enclosure with an internal volume of 2.0 cu/ft with one 4" diameter x 13.625" long port. This equates to a tuning frequency of 30 Hz. They also recommend using a sub-sonic filter.

Sealed Bandpass Box: When using a bandpass enclosure Infinity recommends a sealed rear chamber volume of 1.0 cu/ft and a ported front chamber volume of 1.0 cu/ft with a 4" diameter x 6.625" long port. This equates to a tuning frequency of 60 Hz. They also recommend using a sub-sonic filter.

Free-air Mounting: In addition to being compatible with sealed, ported, and bandpass enclosures, the woofer can be used in free-air applications. A free-air subwoofer is designed to be mounted on a baffle board, which separates the front of the speaker from the back. For instance, you could mount this woofer to a board attached to the rear deck or placed in the trunk against the rear seat. The trunk acts as the enclosure housing the subwoofer. Because there is no specific volume of air to stiffen the suspension, the free-air power handling is approximately half that of the woofer in a box, in this case 175 watts RMS.

Specifications

Thiele-Small Parameters: Because the woofer has two impedance settings, there are two sets of Thiele-Small parameters:

 
DC Resistance (Ω) 2.1 4.3
Inductance (mH) 1.18 1.18
Vas (liters) 54.43 54.43
Qms 4.38 2.47
Qes 0.51 0.52
Qts 0.46 0.43
Fs (Hz) 27.2 27.2
Radiating Area (m²) 0.05188 0.05188
Xmax (mm) 17.5 17.5
Motor Force Factor (TM) 12.47 18.37

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Customer Q&A

Q
Crutchfield asked: Why did you buy this?
A
I bought an infinity kappa sub woofer in 1998 it still works bought a JL in 2005 five does not work anymore if you're looking for quality and longevity infinity is the only way to go [ ROBERT  May 07, 2016 ]
A
Infinity sounds great! [ Jeremiah  Mar 07, 2016 ]

6 questions already asked

Q
Are the voice coil switches separate so one coil can be at 2 ohms and the other at 4 ohms so that when wired in series they present a 6 ohm load to the amplifier?
[ Fred  Jun 02, 2016 ]
1 answer
A
The Infinity 120.9w is a single voice coil model with an adjustable impedance switch that sets the woofer to either 2 or 4-ohm. There wouldn't be any way to present a 6-ohm load to your amplifier with this model. I hope that helps. My Bio: http://www.crutchfield.com/Support/Bio.aspx?bio=159
[ Larry  Jun 04, 2016 ]  Staff
Q
Can one coil be set at 2 ohms and the other at 4 ohms for a total of 6 ohms when wired in series?
[ Fred  May 31, 2016 ]
1 answer
A
there's a selector switch that allows you to pick between two or four ohms no way wiring sequence
[ ROBERT  May 31, 2016 ]
Q
How much does the sub stick out of the box when it is mounted?
[ Rusty  Dec 07, 2015 ]
1 answer
A
It will stick out 0.75" past the mounting surface.
[ Paul  Dec 09, 2015 ]  Staff
Q
I have a Kenwood amp that puts out 500 watts at 2 ohms. Would that be too much pushing through this sub, or will it be fine?
[ Russell  Dec 04, 2015 ]
1 answer
A
That amp can power this subwoofer and you shouldn't have to run the amp at full output either.
[ Paul  Dec 06, 2015 ]  Staff
Q
Cuts in and out randomly. When it goes out, if I give the enclosure box a good slap, it often comes back on again. How can I get it to stop cutting out though? I am confident in the amp and amp wiring. The sub (and enclosure) were purchased second hand online, and I do not know what the wiring looks like inside the enclosure.
[ Tracy  Dec 27, 2013 ]
2 answers
A
Thanks, Jeff. Yes, that worked. I tightened up all the connections, and it works great now! No more cutting in and out. Sub is A W E S O M E !!!!!!
[ Tracy  Jan 01, 2014 ]
A
This sounds like a loose connection somewhere inside the box. I would recommend checking that wiring first.
[ Jeff  Dec 27, 2013 ]  Staff
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