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RE Audio SX18D4

1000W 18" SX Series Dual 4 ohm Subwoofer

In Stock. Only 3 Left!

List price $824.99

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RE Audio SX Subwoofers

RE Audio raises the bar for high output with the SX line of their competition grade, high excursion subwoofers. With an impressive power handling rating of 1000 Watts RMS – this subwoofer shows you it’s meant for those serious about quality bass.

Every single component of this subwoofer has been crafted with precision in mind to obtain full, impactful bass. From its 3” eight layer aluminum flat voice coil, to its triple stacked magnets this high powered subwoofer will output with fine clarity.

The entire SX line of subwoofers can handle an impressive 1000 watts of RMS continuous power, no matter the size! With its large Rubatek Foam surround and FEA optimized motor structure; this woofer can handle large amounts of power, while maintaining durability. The RE Audio SXX Subwoofers series is certainly one subwoofer manufactured with hi-fidelity audio in mind.

Subwoofer Features:
  • 18" Dual 4 ohm SX Series Car Subwoofer
  • Power Handling:
    • RMS: 1000 watts
  • Impedance: 4 ohm
  • Dual composite 2-piece cone
  • Rubbertek Foam Surround
  • Tork-Tite terminals
  • Cast aluminum basket
  • 3" 8-layer aluminum voice coil
  • Triple stack magnets
  • Hand-built in the USA
  • Authorized Internet Dealer
  • 1-year Manufacturer's warranty

Subwoofer Dimensions:

  • Mounting Depth: 9.5"
  • Mounting Hole Diameter: 16.75"
  • Overall Diameter: 18.5"
  • Bolt Hole Circle: 17.5"
  • Motor Width: 6.5"
  • Motor Depth: 3.25"
  • Basket Depth: 6.25"
  • Displacement: 0.22 cu. ft.
  • Weight: 28 lbs.
SX 18" T/S Parameters
  • Electrical Q Value -Qes: 0.53
  • Mechanical Q Value -Qms: 6.1
  • Total Speaker Q Value -Qts: 0.48
  • Free Air Resonance -Fs: 33.2 Hz
  • Equivalent Compliance -Vas: 159 liters
  • One-Way, Linear Excursion -Xmax: 22 mm
  • Efficiency -SPL 1W/1m: 92.7 dB SPL
  • Effective Piston Area -Sd: 1210 cm^2
  • DC Resistance -Re: 1.9 ohm
  • Nominal Impedance -Znom: Dual 4 ohm
  • Thermal Power Handling -Pe: 1000 W
  • Force Factor -Bl: 21

For more information on the Thiele and Small Parameters, visit our T/S Parameters Article

Product History:

(newest, current model)
RE Audio SX18D4 thumbnail
(previous model, replaced by RE Audio SXX 18 (SXX18D4))

Subwoofer Specifications

Subwoofer Series
Each subwoofer manufactured is part of a series. This is the name of the subwoofer's series.
SX (RE Audio)
Subwoofer Size
Refers to the diameter of the subwoofer, measured in inches.
RMS Power Handling
The RMS power is the amount of power the speaker requires to operate safely and properly. RMS Power Handling refers to the amount of power a speaker can handle on a continuous basis. We recommend powering your speakers or subwoofer with 80%-120% of its recommended RMS rating. The RMS power handling specification is typically rated per speaker unless otherwise noted.
1000 watts
Voice Coil(s)
Dual voice coil subs have more wiring flexibility than single voice coils subs; however, single voice coil subwoofers provide easier hookup options for wiring multiple subwoofers in parallel or series. You may also run a dual voice coil (DVC) sub in parallel, series, or combination. A quad voice coil has four voice coils and is equal to two dual voice coil subwoofers as far as wiring goes.
Impedance (Per Voice Coil)
The load value (in ohms) that the speakers present to the amplifier per voice coil - the amount of resistance to the current flow. This is a key specification as subs wired in parallel or low impedances can create problems with your amplifier and potentially void all warranties. We encourage you to ask our support department prior to purchase if you do not understand which impedance level will suit your application best.
4 ohms
Voice Coil Diameter
Diameter of voice coil, usually measured in inches.
An efficiency or sensitivity rating tells you how effectively a speaker converts power into sound. The higher the number, the more efficient the speaker and the louder it will play with the same input power. An efficient speaker helps you maximize your available power. Most sensitivity ratings measure the speaker's output with 1 watt of input, 1 meter from the speaker. Some speakers' sensitivity is measured with 2.83 volts of input, instead of 1 watt.
Efficiency (1w/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other speakers or subwoofers to determine which one is "louder".
92.7 dB
Xmax (millimeters)
Typically measured in millimeters, the Xmax value is the measure of a speaker cone's maximum excursion in one direction while maintaining a linear behavior.
22 mm
Subwoofer Design
This is the design of the subwoofer or the opening of the subwoofer enclosure. Each design has it's own benefits, whether it is a square, circle, or oval.

Round/Circle: This is the typical and common subwoofer design. They have a round cone and are a circle in design.

Square: These woofers are able to achieve a greater cone area in a smaller space. Because of the greater surface area, some square subwoofers will be louder than a round subwoofer of the same size.

Round / Circle
Main Cone Color
This is the color of the speaker's or subwoofer's cone.
Woofer Composition
Lightweight woofer cone materials are essential for efficient operation. Poly cones produce exceptional sound and are sturdy against various changes in temperature. Paper cones are very efficient, and when treated for moisture resistance, will perform at a high level. Poly refers to polypropylene, which is thermoplastic or fibers that are polymers of propylene. IMPP refers to injection molded polypropylene, a commonly used process and material in speakers.
Dual composite 2-piece cone
Woofer Surround
A speakers surround is part of the suspension system. The surround protects the cone and prevents it from being displaced as it flexes out from the basket. It is usually made of a durable material like treated foam or rubber in order to withstand the strenuous job of producing bass frequencies.
Rubatek Foam
Magnet Structure
Defines the overall structure of the subwoofers magnet.
Triple Stacked
Subwoofer Grille
Most subwoofers are able to accommodate a universal grille; however, some subs include a grille and others have a specific, optional grille available for purchase separately. If "yes", then the subwoofer includes a grille. If "optional (sold separately)" the matching grille will need to be purchased in addition to the sub.
Re-Cone Kit Available
Some higher end subwoofers have replaceable cone assemblies. In case of a blown woofer, a recone kit allows for a simple replacement, as opposed to purchasing an entire new subwoofer.

Recommended Enclosure Specifications

Recommended Enclosure Type
This is the recommended type of enclosure that the subwoofer should be installed into. Some subwoofers are specially designed for particular enclosures.

Sealed: These enclosures completely enclose the air inside the box. These boxes produce a tight bass.

Ported/Vented: These enclosures have a slot of air to escape from the box. The result is a sound that has more "boom".

Bandpass: These are a combination of both sealed and ported enclosures. They can be very efficient, but require tuning for the best response.

Ported / Vented
Minimum Ported Box Volume
This value indicates the minimum ported box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.
5.5 cubic feet
Maximum Ported Box Volume
This value indicates the maximum ported box volume that the manufacturer recommends for the subwoofer. The volume is typically displayed in cubic feet.
8.0 cubic feet
Top-Mount Depth
The depth when installed on top of the mounting surface. Measured from the bottom of the speaker's magnet to the bottom of the mounting holes on the rim of the speaker.
Cutout Diameter
The actual diameter of the hole you will need to cut out if you are creating a new mounting location for this speaker, or if you are mounting a subwoofer in a box.
Shallow Mount Installation
This means that the subwoofer/speaker is designed to be installed in areas that do not have a lot of space. Shallow mount subwoofers are typically found under a seat or behind the seat in some trucks.

Shallow mount speakers will typically have a mounting depth of 2" or less, while shallow mount subwoofers will typically have a mounting depth of 3" or less.


Electromechanical Parameters

Free-Air Resonance (Fs)
The free-air resonance frequency of the subwoofer, measured in Hz. At this frequency the weight of the moving parts is perfectly balanced with the subwoofers suspension system.
33.2 Hz
Equivalent Compliance (Vas)
This is the amount of air that has the same stiffness as the subwoofers suspension. The greater the rating, the lower the stiffness and larger recommended enclosure. It is measured in Liters.
159 liters
Total Speaker Q Value (Qts)
This is the subwoofers relative damping (Q) at the resonance frequency (Fs), including all dimensionless losses. Essentially, a high Qts value (closer to 1.0) means the subwoofer is great for sealed enclosures and a low Qts value (closer to 0) means the woofer is great in vented enclosures. A Qts of around 0.45 means the woofer will work decently in either enclosure type.
Electrical Q Value (Qes)
The subwoofers relative damping (Q) at the resonance frequency (Fs), including electrical losses. Also called the mechanical damping of the subwoofer. The unitless measurement usually varies from 0.5 – 10.
Electrical Resistance of Voice Coil (Re)
Amount of DC resistance of the subwoofer when measured with an ohm meter. Typically, this will read less than the impedance rating of the subwoofer.
1.9 ohms
Mechanical Q Value (Qms)
This is the subwoofers relative damping (Q) at the resonance frequency (Fs), including mechanical losses. Also called the mechanical damping of the subwoofer. This unitless measurement usually varies from 0.5 – 10.

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
4 Star
3 Star
2 Star
1 Star

Average Attribution Rating




October 6, 2011

I bought this amazing shipping time, good quality!!!!!!

17 of 29 found this helpful

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Houma, LA

Great Subwoofer

December 15, 2011

This thing is LOUD. Some people claimed that this subwoofer was only good for SPL and that it lacked sound quality. Well I'm nothing but impressed with this thing. I have it in a 1.2 cubic foot box tuned to 28 Hz in the back of a 20006 Expedition Limited. People are shocked when they hear how loud and low it gets.

Pros: Priced fairly, LOUD, DEEP, durable

Cons: Takes up a lot of room, things in my car are starting to break, (Specifically in my doors) Hearing loss.

18 of 32 found this helpful

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Very good value

October 19, 2012

The RE SX18D4 are awesome subs for entry level as well as the serious competitor.

16 of 30 found this helpful

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GOOD 18? 4 the price$$$

May 31, 2011


13 of 24 found this helpful

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Kingman, AZ

Awesome Sub!

October 13, 2014

This sub is impressive! It may be rated 1000 watts thermal power handling but if it were rated 2000 watts RMS, it would be conservative. The XMAX on this sub is true and not just total linear movement. I am using it for car audio competition and it doesn't disappoint,150+ db by itself in stock and street beat. Plus, that is without beginning to tune and modify to gain ever little db possible. This thing has an incredible voice coil when you look at it through the spider. This thing is built to last, pound and made in USA! This is one of the most incredible subs I have ever seen in its class. If you buy this thing, you made the right decision, you won't be disappointed.

14 of 27 found this helpful

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Dothan Alabama

all i can say is Baaaaaaassssssss!!!

February 13, 2013

I have 2 of these monster in my suv and damn,,,,,real top of the line hard hitters i love them,matter of fact im thinkin bout ordering 2 more

14 of 27 found this helpful

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Mike Frost

Fort Lewis, WA

Great product

June 12, 2012

I have 2 of these running off of a Hifonics Zeus ZRX 3000 and its crazy. Break them in properly and they will be your friend forever. I have them ported through my rear dash and if I try to look into the port it has me breathing like Hannibal Lecter in "Silence of the Lambs" when he said "I ate his liver with some Fava beans and a nice Chianti"

13 of 27 found this helpful

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Toledhoe, Ohiyo

Durable DD sub

April 23, 2012

I am currently running 2 RE Audio SX18D4 subs off of an Audioque AQ3500.1D amplifier @ 1 ohm. The subs are rated at 1000 watts rms, and the amplifier puts out 4300 watts rms @ 1 ohm. Yeah these are that durable and under rated. I honestly didn't expect them to last very long at all. The truck has a 320 amp alt, 2 yellowtops, 4 runs of 0 ga, and 8ga wire to each sub so the amp is giving them hell, and they just slam and take it. I only smell the voice coils when it hits the low 15-25hz notes for long periods of time. With clean clip free power, these subs will play forever on around 1k watts. I had them on a Hifonics BRZ2400.1D and it could really only make one loud at a time. They have a sweet spot for longevity and sound at somewhere around 1500 watts rms.

14 of 30 found this helpful

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Grayling mi

Great sub

October 25, 2012

This sub is pretty damn wicked ive never owned an 18 before ive always had 12s and this sub blows my 2 alpine type rs out of the water easliy hits 156db no problem with only 1k rms to it dont let the specs fool you on the box size 6 cubes is as big as you should go on it and this sub has at least 3 in of excursion to it. its a wonderful sub would by it again.

11 of 25 found this helpful

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Portage, WI

A Monster

January 31, 2012

I got this thing shipped across the country in 6 days. It's way bigger in person. The spider is stiff as a board. Be sure to ease into flexing the thing at full tilt. I had it running free air on 2000 watts at 4 ohms. I couldn't push the cone up or down but apparently when 2000 watts of power is pushing it, it has an inch of excursion. It shook my truck more than my two orion 10's AND ITS NOT EVEN IN THE BOX YET.
I put it in a 10ft. cubed box sealed. When the low note hit on White Girl, all i could do is laugh and gasp for air. I went inside my restaurant because thats the only place i could test this thing without the cops being called. I could feel the bass on the counters! And the doors were shaking. I was around 15 feet away from the door at the time. I went home and on my way there i stopped at a red light. Obviously i turned it up to the Maxx and the trucks tailgate in front of me was rattling. I AM TRULY PLEASED WITH THE RUCKUS I CAN CAUSE WITH THIS THING.

16 of 35 found this helpful

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sweeny, texas

awesome speakers

September 2, 2014

i was very pleased with the packaging,. I ran rockford fosgate 18s for approximately 7 years strait and i recently purchased the RE Audio SX18D4 speakers. Ive had them for about 3 weeks and they are starting to break in. They work nicely. I have had several good comments on how well they sound and we will see if they hold up because im not your average listenor. I play my system on the average of two hours a day 7 days a week, so far so good. any comments or want to see video 979-549-7972

13 of 30 found this helpful

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huron, OH


October 22, 2014

This is an awesome sub for the price, good and loud. Good quality too, I have it in a 7.6 cu. ft. Box tuned to 40 hz. I would recommend a smaller box because right around 25 hz it starts fluttering. Probably 5.5 cu. Ft. Would be perfect.

9 of 23 found this helpful

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Phoenix, AZ

2 18's re audio sx

April 2, 2012

these speakers pound so hard, each 18 is ran by 1000/1 jl amp..

11 of 27 found this helpful

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Accessory Tools and Products

Accessories added

NVX 20 ft. of True Spec 8 Gauge Speaker Wire

Flexible multi-strand cable bends and twists to meet your installation needs.

Your Price $49.99

25 ft. of Streetwires 12 Gauge Speaker Cable

You'll need speaker wire to hook up that new subwoofer!

Your Price $44.95

Belva 23 ft. of 12 Gauge Speaker Wire

Ultra-flexible PVC blended jacket for easy installation.

Your Price $14.99

40 Square Feet of Sound Dampening Material

Thicker than the competition, complete sound damping kit for entire vehicle! Use for trunk, doors, roof and floor.

Your Price $119.99

Dynamat Sound Dampening Bulk Kit

Did you know sound dampening will reduce those annoying rattles and even increase your SPL?

Your Price $159.99

Stinger Sound Dampening Bulk Kit

Stinger's Roadkill sound dampening series is sure to kill unwanted road noise and rattles! Enough sound dampening for the whole car!

Your Price $99.99

40" x 15 Ft Piece of Premium Un-Backed Automotive Trim Carpet

Durable design for long life-span, available in many colors and shades.

Your Price $39.99

Gold Plated Dual Terminal Banana Plug Connector

Enables an expandable, secure connection accepting up to 8 gauge wire.

Your Price $1.99

2" Universal, Professional Heavy Duty Roller for Sound Damping/Dampening

Universal rubber roller to make it easy to install sound dampening.

Your Price $7.99

Car Stereo and Speaker Installation Tool Kit

Includes Test Light, Crimp/Splice Tool, Multi-bit Screwdriver and more.

Your Price $16.99

Xscorpion 9-Piece Nylon Plastic Pry and Chisel Tool Set

Easily removes dash/trims, door clips, panels and pins, rubber grommets and vehicle emblems.

Your Price $14.99

1mm All Purpose Solder

Solder is all purpose for use on most projects where solder is needed.

Your Price $8.99

Scosche SPL Meter

Monitor the noise level of your new car audio system with this SPL meter measuring from 60-135 dB.

Your Price $21.99

1 RE Audio SX18D4 Subwoofer

Mono Amp

2 Channel Amp - Bridged

2 RE Audio SX18D4 Subwoofers

Mono Amp

Mono Amp - Option 1

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp - Bridged

3 RE Audio SX18D4 Subwoofers

Mono Amp

4 Channel Amp

4 RE Audio SX18D4 Subwoofers

Mono Amp

2 Channel Amp

2 Channel Amp - Bridged

4 Channel Amp

Browse 1 question and 1 answer
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Hola, cuando llega el stock ?
abigliazzi on Mar 5, 2015
Best Answer: (RE Audio) ETA: 2015-03-27
Reply · Report · Customer SStaff on Mar 5, 2015
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Product Summary


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Internal Product ID


Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: RE Audio SX18D4

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