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JBL S3-1224

Series III 12" component subwoofer with impedance switching

Item # 109S31224

California customers:
Please click here for your Proposition 65 warning.

Discontinued item
4 questions - 5 answers

Item # 109S31224

About the JBL S3-1224

Quality and power

JBL has stood for quality ever since they first began manufacturing audio components back in 1946. Their Series III subwoofers will bring some serious bass to your vehicle, with a strong emphasis on power handling.

The Series III S3-1224 12" sub handles up to 500 watts RMS, and it's optimized for use in a very small sealed enclosure. JBL uses the airflow from the motor to cool the 2-1/2" voice coil, so you can rely on this sub to stay cool in the heat of battle. The sturdy polypropylene cone and nitrile rubber surround will stand up all the abuses of heavy bass output.

Selectable impedance

The Series III subwoofers also feature SSI™ (Selectable Smart Impedance), a switch which lets you vary the sub's impedance from 2 ohms to 4 ohms to optimize its effectiveness with your system. If you upgrade your amplifier or decide to add another sub, you'll be able to adjust the S3-1224's impedance to match.

Versatile power

The terminals on this Series III sub will accept up to 8-gauge wire. You'll get full power from your amp even over long wire runs, so you and your subwoofer have the juice you need. See what this JBL sub can do for your system.

Product highlights:

  • 12" high performance car audio subwoofer
  • polypropylene cone
  • nitrile rubber surround
  • stamped steel vented basket
  • handles up to 500 watts RMS (1500 watts peak)
  • frequency response: 25-175 Hz
  • sensitivity at 2.83V: 92dB
  • voice coil diameter: 2-1/2"
  • impedance: 2 or 4 ohms switchable
  • mounting depth: 7"
  • mounting height: 3/4"
  • sealed box volume: 0.75 cubic feet
  • ported box volume: 2.5 cubic feet
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # S3-1224

What's in the box:

  • One 12" Subwoofer (with impedance switch)
  • Eight 1" Self-tapping screws (4mm Allen head)
  • 8 Screw spacers
  • Owner's manual

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Product Research


Selectable Smart Impedance (SSI): A switch on the input terminal allows you to easily change the woofer's impedance between 2Ω and 4Ω settings. (The connected amplifier should be off when changing the impedance.)

NBR Surround: Nitrile butadiene rubber (NBR) is a synthetic rubber, well-suited for automotive woofer surround applications. It is durable, can withstand a wide range of temperatures (-40 to 226 °F), and is resistant to breakdown due to UV light exposure.

Terminal: The set screw wire terminals will accept bare wire up to 10 gauge and are tightened/loosened with a 2.5mm Allen wrench (not included).

Enclosure Recommendations:

  • Sealed Box Volume: 0.75 ft³
  • Ported Box Volume: 2.5 ft³ with one 4" diameter x 11.7" long port (tuned to 30 Hz)
  • Infinite Baffle: The woofer can also be mounted in free air to a baffle board (no enclosure). When mounted in free air, the power handling is lowered to 250 watts RMS.
  • Band Pass: A prefabricated band pass enclosure is also mentioned in the manual as acceptable, but no specific size or tuning recommendations are listed.

Thiele-Small Parameters: Some of the parameters change based on the impedance setting:

Re (Ω) 1.82 4.07
Le (mH) 1.03 0.94
Sd (cm²) 530.93 530.93
Bl (Tm) 11.70 16.99
Vas (liters) 54.65 52.59
Fs (Hz) 28.84 29.07
Qms 4.29 2.56
Qes 0.53 0.58
Qts 0.47 0.47
Xmax (mm) 12 12

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Customer Q&A

4 questions already asked

Which sub is better this JBL or digital designs redline 612 ?
[ Nasheel  Sep 10, 2017 ]
2 answers
I dont know about the 612 but the JBL in the right size enclosure is great!
[ JONATHAN  Sep 11, 2017 ]
I would do DD over this. When I had this JBL it did not impress me at all.
[ Daril  Sep 11, 2017 ]
Is this better that a Kicker CompR 12"?
[ Helaman  Feb 19, 2016 ]
1 answer
Thanks for your question. For information on comparing two or more models I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences and help you make the best choice for your system and your budget.
[ Krissy  Feb 19, 2016 ]  Staff
How do i wire 4 jbl s3-1224 would like know trying to get them at 1ohm stable ? but cant figure it my 3000d.1 mono can handle 2100 rms watts at 1ohm
[ wilfredo  Oct 01, 2015 ]
1 answer
You can see a diagram of how to wire the speakers here: Keep in mind that you'll want to be sure your amplifier is 1-ohm stable before attempting this type of configuration.
[ Jeff  Oct 05, 2015 ]  Staff
How much performance can I expect using this with a GTX500 (2Ohm) in a Sealed Box?
[ Chris  Aug 05, 2015 ]
1 answer
I forwarded your question to an Advisor and they responded with the following: The amplifier and subwoofer is an excellent match so you should get the full potential from the JBL S3-1224 subwoofer. It is definitely a very strong performing subwoofer so it should sound fantastic. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat.
[ Krissy  Aug 12, 2015 ]  Staff

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