JBL S3-1224 **Toggle between 2-Ohm & 4-Ohm Impedance!**

1500w 12" Series III Subwoofer with Selectable 2-Ohm or 4-Ohm Impedance

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• 500 Watts RMS
• Polypropylene Cone
• Nitrile Butadiene Rubber (NBR) Surround
• SSI™ (Selectable Smart Impedance)
• Oversized 3.0" Voice Coil
• Premium 8 AWG Screw-down Terminals
• Sensitivity: 92 dB

Learn more about the s31224

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This item has been discontinued

Product Highlights

• 500 Watts RMS
• Polypropylene Cone
• Nitrile Butadiene Rubber (NBR) Surround
• SSI™ (Selectable Smart Impedance)
• Oversized 3.0" Voice Coil
• Premium 8 AWG Screw-down Terminals
• Sensitivity: 92 dB


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JBL S3-1024
12" (300mm) High-Performance Car Audio Subwoofer

JBL believes sound quality should never be compromised. And Series III subwoofers make sure you don't have to compromise flexibility, either. That's because the high-performance, step-up subwoofers feature SSI (Selectable Smart Impedance), an exclusive impedance switch that lets you select the optimum impedance—2 or 4 ohms—for your system. Special aero-cooling design in the voice coil boosts power handling as well as reliability. And an oversized voice coil handles more power than common two-inch voice coils. More power, more reliability, more flexibility—and no compromising. When you're ready to step up, Series III is your subwoofer.

Key Features:

    SSI (Selectable Smart Impedance)

    Most car audio system designs call for 2- or 4-ohm impedance. Series III subwoofers feature an exclusive dual impedance switch that lets you choose either load impedance option. Not available from any other manufacturer, SSI lets you reconfigure your system by simply flipping a switch.

    Aero-cooled voice coil

    The Series III voice coil significantly increases power handling and improves reliability by going with the flow—of air. The woofer's motor channels air pumped by the cone movement past the voice coil, and the voice coil former exposes the coil's inner and outer surfaces to the airflow. This aero-cooling design is unique among aftermarket subwoofers.

    Oversized voice coil

    The three-inch (75mm) voice coil proves you don't have to be a heavyweight to pack a serious punch. It handles more power than conventional two-inch voice coils, yet it's lighter than four-inch voice coils. It strikes the perfect balance between thermal power handling and low mass.

    Premium screw-down terminals

    Power is the lifeblood of any subwoofer. The terminals on the Series III accommodate up to 8-guage wire (8.37mm2 cross section), which transfers low-resistance, low-loss power to the woofer, even over long wire runs. This ensures the subwoofer—and your music—has the power it needs.

The Sound of quality

Sonic Electronix, one of the leaders in car audio, recently visited Harman, the premium global audio and infotainment group, at their research and development locations in Northridge, California and Detroit, Michigan. The purpose of these visits was to utilize and combine the powerful brand of Harman and the industry leading knowledge behind Sonic Electronix to begin working together on developing future car audio projects.

General Features:

  • 12" Series III High-Performance Car Audio Subwoofer
  • Power Handling:
    • Peak: 1500 watts
    • RMS: 500 watts
  • Nominal Impedance: Single 2 or 4 ohm
  • Polypropylene Cone
  • Nitrile Butadiene Rubber (NBR) Surround
  • SSI (Selectable Smart Impedance)
  • Aero-cooled Voice Coil
  • Oversized 3.0" Voice Coil
  • Premium 8 AWG Screw-down Terminals
  • Stamped Steel Basket Frame
  • Top-mount depth: 7.00"
  • Cutout diameter: 11.125"
  • Frequency Response: 25 ~ 175 Hz
  • Xmax: 12.00 mm
  • Sensitivity: 92 dB
  • Sealed Enclosure Recommendation: 0.75ft³
  • Ported Enclosure Recommendation: 2.50ft³
  • *Infinite-baffle Mountable
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty
  • Priced Individually

Check out the JBL S3-1224 Owner's Manual

*Infinite-baffle mounting is possible, but the subwoofer's mechanical power handling will be reduced because there will be no volume of air to stiffen the subwoofer's suspension and prevent overexcursion. If you choose infinite-baffle mounting, consider the RMS and peak power-handling ratings to be half of what is listed

Tips for Installing the your subwoofer

This item is currently not eligible for our low price guarantee. This may be due to supply constraints, manufacturer restrictions, or another reason. We're always here to help you get the best price possible so give us a call or email today. Our experts will do their best to build the system that works for you within the rules.

Subwoofer Wiring Guide

Wiring Guide to Wire 1 JBL S3-1224 **Toggle between 2-Ohm & 4-Ohm Impedance!** Subwoofer

Mono Amp

Wiring Guide to Wire 2 JBL S3-1224 **Toggle between 2-Ohm & 4-Ohm Impedance!** Subwoofers

Mono Amp

Mono Amp - Option 1

2 Channel Amp

2 Channel Amp - Bridged

Wiring Guide to Wire 3 JBL S3-1224 **Toggle between 2-Ohm & 4-Ohm Impedance!** Subwoofers

4 Channel Amp

Wiring Guide to Wire 4 JBL S3-1224 **Toggle between 2-Ohm & 4-Ohm Impedance!** Subwoofers

Mono Amp

2 Channel Amp

4 Channel Amp

Specifications & Details

Subwoofer Specifications
Subwoofer Size
Peak Power Handling
1500 watts
RMS Power Handling
500 watts
Voice Coil(s)
Impedance (Per Voice Coil)
2 or 4 ohms
Voice Coil Diameter
Frequency Response
25 - 175 Hz
92 dB
Xmax (millimeters)
12.00 mm
Subwoofer Design
Round / Circle
Main Cone Color
Woofer Composition
Woofer Surround
Nitrile Butadiene Rubber NBR
Subwoofer Grille
Re-Cone Kit Available
Recommended Enclosure Specifications
Recommended Enclosure Type
Ported / Vented
Optimum Sealed Box Volume
0.75 cubic feet
Optimum Ported Box Volume
2.50 cubic feet
Top-Mount Depth (Mounting Depth)
Cutout Diameter
Shallow Mount Installation
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Item Details



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Product and How-to Videos

  • Harman International: The Pursuit of Great Sound
  • Car Subwoofer Size Buying Guide | What Size of Sub Should I Get?
  • How to Install a Car Subwoofer in a Box

Customer Ratings & Reviews

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Customer Reviews

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Good at >40hz, Doesn't Handle 30hz well (by itself)

I have used this subwoofer in a sealed box with 0.75 to 0.85 cubic feet volume, running 4 ohms, powered by a Lanzar HTG257 at 40 to 50% gain, no bass boost, LPF around 120 hz, and signal coming from a Sony CDX GT55(not sure about exact model). All this is in a 2002 ford focus hatchback. When installing this subwoofer, I soldered the wires to the tabs provided on the back side of the spring/banana connector piece. I didn't solder the wires to the sub's connectors though, because they were just holes with screws (to hold the wire) surrounded by plastic. I didn't want to mess it up. So I just tinned the wire ends before tightening them down in the sub's connection points.

Two 10s vs This 12
It tends to produce 40-45 hz more than my old dual 10's, but I think it is lacking some punch that the 10's could generate. I like hardstyle and hard trance, so I want my sub to be able to get that high bass thud, but also enjoy occasionally cranking some tunes with less than 40 hz notes. Overall, though, the loudness was almost the same as the dual 10's when using the exact same amp gain/settings.

At only 50% amp gain (no bass boost), this single sub will start rattling my car a little. I usually only go to +6 on my head unit's sub output (with +0 on the bass equalizer option). Now my amp supposedly only produces a max of 300 watts RMS, so I am only pumping about 110 to 170 watts into this thing. I thought that since it is rated for 500 RMS, I would be totally fine blasting any song. WRONG! I THINK I STARTED TO BOTTOM THIS SUB OUT WHEN PLAYING 30 HZ AT PROBABLY LESS THAN 200 WATTS! With my amp at 50% gain, I started slowly turning the sub output up. It gradually got louder until one point where it didn't increase volume, but instead changed tone. Increasing the sub signal beyond that point made the sub sound quieter. I was confused, so I went back to look at the sub and found that it was probably hitting max excursion. I didn't measure it (don't know how to measure displacement of a moving sub), but it definitely looked like it was going in and out around 3/8" or more. If you haven't checked the max for this sub, it's 0.47". So I am a little disappointed, because I had hoped the lower frequency response of this sub would allow it to play lower frequencies louder than my 10's. If you had two of these, you could probably thump some 30hz like crazy before hurting these things though.

This Sub looks pretty cool in my opinion, but it's pretty heavy. I haven't felt other subs of this caliber, though. So I don't have much to compare it to. The main reason I bought this was because I wanted more trunk space. My dual 10s had a box that was actually too large, so it took up almost my entire trunk. I got them for free though, so I'm going to pass them on to someone else. This sub in a sealed box, on the other hand, is quite small and still loud. I keep my sub output around -6 for normal listening.

When I first was looking to replace my 10's, I didn't want to spend the extra money on this sub versus an american bass XD-1244. My older brother (audio/videophile) told me to get this one, however, because JBL usually under-rates their stuff and make good stuff.

By Brandon on July 10, 2017


found this helpful.

Loud clean sound

I bought 2 of these while on sale here at sonicelectronix. I put them in a ported box with about 1.6 cubic ft each. These subs sounds very clean and have great range. They do prefer punchier bass as they get very loud without breaking a sweat. I recently upgraded my amp to a true 500watt rms to each. They still sound clear and do not get too warm at rated rms. I really like the ssl switch. If you want to change your impedance due to adding a sub or wiring down an amp to meet dif loads you can. That alone will save you time and money. We all want to upgrade our bass over time and they allow easy cost effective solution. Only downside is that they are not on sale at the same price. I'm assuming this is due to the popularity to this new product. Thanks sonic

By Cballaholla on September 8, 2016


found this helpful.

Excellent subwoofer.

This JBL sub is a beast.I have the JBL S2-1224 and upgraded to JBL S3-1224 hooked up to a JBL Ms-A5001
Digital signal processing amplifer at 4 Ohms. It's definitely worth the money, and Sonic gave me a great deal. Thanks

By elgin on February 24, 2018 Checkmark Icon Verified purchase


found this helpful.

Hits Hard

I purchased this with amp kit and JBL GTX500 amp. I am running a 2 ohms in a sedan and have amp gain only at 40%. This thing hits hard in a 2.4cf ported box, if i turn it up anymore it drowns out my mids and highs..hits just as hard as friends 2 mtx 12s in a sealed box. Good kit and good product

By Rob on November 7, 2016


found this helpful.

great subs!!

these subs are great, they looking, sounds excellent and packs a helluva punch!!

By smitty87 on October 3, 2016 Checkmark Icon Verified purchase


found this helpful.

Very Underrated

So I've always been a fan of JBL but never really thought of buying their subs but thought I would try this one as a SQ sub and this sub has been absolutely amazing I am putting 600 watts to it and I have a pair of them in a sealed box and I couldn't be happier I like them more than any sub I have owned and heard (work at an audio store working with kicker Polk alpine pioneer and Rockford and at this price point and even those a couple hundred more don't even touch this sub especially as far as quality goes. Would recommend to any and all except those that use dirty power amps and constantly blow subs.

By AD on September 16, 2016


found this helpful.

My 2nd new subwoofer

first the sub looks nice and looks well built. my first sub was a JLd12d3 @ 2ohms it hit hard in port box, but it blew being under powered. This JBL hits hard also @ 2ohms paired with Apline m-500 @ 2 ohms 500 rms match up sub nicely. been breaking it in, but i can tell it sounds good even before it has been fully broken into. rewired my amp to 8 gauge wire and my sub loves it. its nice that the sub can take 8 gauge wire getting all the power it needs for deep pounding bass. im happy with my purchase hope it lasts me a long time

By blaze2051 on April 24, 2016


found this helpful.

Fantastic Subwoofer!!!

I have this on a Kicker 500w at 4ohms and the bass is awesome! I was a little scare that this wouldn't be enough power to complement my system but it was spot on! The selector thing is pretty cool, but kind of a gimmick I think...I guess if I add another one later it gives me the ability to choose from more amps. idk . Also, less importantly, it looks dam good!! Thanks sonic!!

By Peter on April 7, 2016


found this helpful.

By Steven on June 5, 2023 Checkmark Icon Verified purchase


found this helpful.

Oh my goodness!! :D

I have this JBL S3-1224 wired up at 2 ohms with a Soundstream PN1.650D and have this in a Rockville RSQ12S 0.75 Cu Ft sealed box. I was able to get this whole set with some other things (Like amp wiring kit) at $300.00

Sub - $115 on Sonic Electronix WITH CRAZY DISCOUNT
Amp - $100 on Amazon
Enclosure - $45 on Amazon
Amp wiring kit (NVX XAPK8 without rca) - $33

My friend who has been in car audio for a while talked me into getting a sealed enclosure since he said that ported enclosures can be irritating after a long time. My friend said a sealed box can just about accomplish what a ported box can do if you feed the sub enough power. 500rms is a great amount to work with. He also reminded me that sealed boxes can go lower and sound tighter too.My JBL S3-1224 in a sealed box screams!

No complaints and it does what it was designed to do. It's super loud. Can easily overpower my (for now) OEM speakers. The SQ is also there (With help of sealed box)

Cons: Only complaints were the lead wires would slap on the cone, so I had to do some zip ties on that, but other than that. couldn't be happier.

By Bear75 on October 27, 2016


found this helpful.


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