Kicker 40CWRT671

CompRT shallow-mount 6-3/4" subwoofer with dual 1-ohm voice coils

Item #: 2064CRT671

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5 Reviews

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A thin sub with big sub bass

If you're looking for bass for a tight space, Kicker designed their CompRT subs with compact cars, pickup trucks, and even motorcycles in mind. The low-profile 40CWRT671 6-3/4” subwoofer performs just like a full-size sub, but without killing all your cargo space. This high-performance CompRT sub stands less than 3" tall, so your installation options are wide open.

Kicker 40CWRT671

This sub clocks in at less than 3" deep.

Built with boom in mind

The 40CWRT671 comes equipped with a rigid injection-molded polypropylene cone that won't flex and cause distortion while you're cranking the bass. Its rubber surround will last through years of heavy use, combining with a special-design back and top plate to give you more excursion (which equals more bass) than other skinny subs.   

Made to work with many systems

This sub handles up to 150 watts RMS so make sure you've got a solid amp to power it, and Kicker offers a compact PX Series amp that's a great match if you're trying to save space. You can wire the dual voice coils for either 2- or 1/2-ohm total impedance, giving you more wiring options when setting up your system. This sub sounds great in a sealed enclosure.

Important Note: If you are wiring this DVC sub for extremely low impedance, make sure that your amp is compatible. You can damage or destroy your amp by exceeding recommended minimum impedance.

To drive this single subwoofer, we recommend a mono amplifier rated between 120 and 225 watts RMS at 2 ohms. For more information, please refer to our article on How to Match Subwoofers and Amplifiers.

Product Highlights:

  • 6-3/4" subwoofer with dual 1-ohm voice coils
  • injection-molded polypropylene cone
  • rubber surround
  • power handling: 50-150 watts RMS (75 watts per coil)
  • peak power handling: 300 watts
  • frequency response: 30-500 Hz
  • sensitivity: 84.6 dB
  • top-mount depth: 2-3/4"
  • sealed box volume: .18 - .75 cu. ft.
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's a component sub and why would I want one?

A component sub is simply a speaker that's designed to reproduce bass once it's installed in a compatible enclosure. Think about the impact of a movie soundtrack in a big theater or even in your own home HDTV setup. A component sub can add the same kind of power to the music in your car. And a car sub is not all about the boom that you hear on a street corner (although that's cool too) - you can pair a component sub with your choice of enclosure to get bass just the way you like it, from tight and punchy to fat and loose. And once you experience music in your car with a well-tuned subwoofer, you'll never go back.

Kicker 40CWRT671 Reviews

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Kicker 40CWRT671

Written By MrH, Wyoming on Monday, May 04, 2015

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Ease of Use
  • Sound Quality
  • Value

Typical Kicker product, Awesome

Cons: none, just realize they are 6.5", not 15's. Don't expect 15" bass

Step One upgrades

Written By ALLAMERSVR, Texas on Wednesday, April 22, 2015

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Ease of Use
  • Sound Quality
  • Value

What can you say about Kicker products that hasn't already been said ? My only reason I did Five stars on Value and Build Quality is they are now built in CHINA. Three stars on Ease of Use is because I was replacing factory speakers and the holes do not line up perfectly. It's FOUR holes guy why can we not get together on this? The Alpine amp was a simple install. But did not like the fact that there is not a separate wire to turn on the amp. Would have been OK but the Monsoon amp that I am using to feed the Alpine had to find the right four wires for a good signal to turn on amp

Pros: Amp is a super simple install. Again Kickers what's to say

Cons: Speakers were approx. 1/8 inch too deep to fit in installed location without "buzzing" or rattling the mounts

Kicker Sub Woofer

Written By Bob, Nevada on Wednesday, December 10, 2014

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Ease of Use
  • Sound Quality
  • Value

I bought this Sub Woofer because it fits in the stock location in my 2006 Jeep Wrangler. I read the reviews and there was one person who had had the same car as i do. He said it didnt preform very well. I think the solution is to install a mono sub amp. I installed a Kicker 12cx3001- 300w X 1 sub woofer amp and this combo gives me all the bass i could ever use. Also Crutchfield was there when i had a question on wiring the sub because it is duel coil so you car wire it in series or parallel. It makes a great combo for my Jeep.

Pros: Everything about this Sub is great

Cons: Non that i have run into.

Powerhouse for what it is

Written By Coreshot, Boulder, CO on Thursday, April 03, 2014

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Ease of Use
  • Sound Quality
  • Value

Installed one month ago into an Audi A6 Avant.

I've had the $5k stereo- two Kicker Solobaric 12s, each running off their own amp, upgraded alternator with a 5 farad cap..... I wasn't expecting that (nor did I really want it anymore).

What I was after was a little depth of sound a little low end thump, and I didn't want to get into my electrical system or give up any cargo space in my Avant.

This little thing is perfect. It installed into a prefab enclosure designed for a 6.5" woofer (with a little trimming), and the whole thing (and the amp! 12PX200.1) installed behind the wheelwell in the side of my trunk, where the factory enclosure and amp used to live.

For what I wanted, it's perfect- doesn't rattle apart the car (but a little dynamat wouldn't hurt) hits the lows, has a bit of rumble, the car's electrical system doesn't even know it's there, and it's a 100% stealth install, even when looking into the cargo area of the vehicle.

Super happy.

Pros: Great power efficiency (1/2 ohm!), needs very little enclosure to sound good, easy to do a stealth install, sounds AWESOME for what it is

Cons: It won't hit like an 8, 10, or 12. Don't expect it to

Kicker 40CWRT671

Written By John, Pottsville, PA on Monday, March 03, 2014

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Ease of Use
  • Sound Quality
  • Value

Bought this sub to replace the factory sub in my '06 Jeep Wrangler that wasn't working when I bought the Jeep used. Choose this one in particular because it is duel 1 ohm like the factory sub. I was expecting to have to modify the console to make it fit and it wasn't too difficult with a dremel. It doesn't sound like much though. I replaced the rest of the speakers too and sometimes I can't tell if it is working. It is a Jeep so there is a lot of competing road noise. Might try some sound deadening to see if this helps.

Pros: Fast shipping, through directions, easy online shopping.

Cons: Lot of money for how it is performing.

Hands-on research

What's in the box?

Download owner's manual

  • One 6-3/4" Subwoofer
  • Kicker logo stickers
  • Manual (English/ Spanish/ German/ French)
  • Template on box

Product Research


Dual 1-ohm Voice Coils: This woofer features dual 1-ohm voice coils, offering wiring flexibility. When the voice coils are wired in parallel the woofer presents a 1/2-ohm load. When the voice coils are wired in series the woofer presents a 2-ohm load.

Tinsel Leads: CompRT subwoofers use Spiralead tinsel-lead technology; the tinsel lead wires are woven into the spider to relieve mechanical stress.

Enclosure Compatibility

Shallow-Mount: Kicker's CompRT series is designed to minimize depth, giving you subwoofer options where standard enclosures don't fit. The vent-less, solid-pole design allows the woofer to be mounted directly against the rear wall of a sealed enclosure.

Recommended Enclosure: Kicker recommends a sealed enclosure for the 40CWRT671 (vented enclosures are not recommended):

  • Minimum Enclosure Volume: 0.18 ft³
  • Maximum Enclosure Volume: 0.75 ft³

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.