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Polk Audio DXi521

5-1/4" 2-way car speakers

26 Reviews | 3 questions - 4 answers

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Item #: 107DXI521

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Was: $99.99

Sale: -$25.00

Installation gear for most cars

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Our take on the Polk Audio DXi521

Go ahead, circle the parking lot till your favorite song is over. Polk Audio's DXi Series speakers will make you want to hit "repeat" so you can hear it all over again. Polk uses a high-tech approach and ideal materials to give your tunes an exciting new edge.

Polk Audio DXi 521

Enjoy your music even more

Go ahead, circle the parking lot till your favorite song is over. Polk Audio's DXi Series speakers will make you want to hit "repeat" so you can hear it all over again. Polk uses a high-tech approach and ideal materials to give your tunes an exciting new edge.

Precision woofers showcase your music

The DXi521 speakers feature 5-1/4" polymer composite cones that are lightweight and stiff, so they can create a big sound with minimal distortion. Polk analyzes their drivers in motion to ensure that cone movement is even and precise. Polk also uses laser imaging to craft woofer cones that are perfectly balanced to resist distortion-causing resonances.

Aluminum dome tweeters broadcast detailed sound

Each 3/4" aluminum dome tweeter brings out the high-frequency highlights in your music, so you'll hear every detail of your most enthralling musical moments. From an intensely quiet acoustic pluck to the most exhilarating electric solo, it'll be a very entertaining ride.

For the size , they produce an awesome sound "quality " sound. Customer service in choosing this speaker was made easier by a caring professional agent

PAxx, Valrico, FL

Featured Video:

What's in the Box:

  • Two 2-way speakers
  • 2 Grilles
  • Eight 1" Self-tapping screws
  • Eight 3/8" Self-tapping screws
  • 8 Speed clips
  • Owner's Manual (English/ Spanish/ French/ German/ Italian/ Portuguese)
  • Online product registration information

Product Highlights:

  • 5-1/4" 2-way cars speakers (pair)
  • polymer composite woofer with butyl rubber surround
  • 3/4" aluminum dome tweeter
  • power range: 2-45 watts RMS (135 watts peak power)
  • frequency response: 60-22,000 Hz
  • sensitivity: 93 dB
  • top-mount depth: 2-5/16"
  • warranty: 1 year
  • Our 60-day money-back guarantee

Polk Audio DXi521 Reviews

Average Customer Review:

26 Reviews

Speaker upgrade

Written by: PAxx from Valrico, FL on May 22, 2016

2015 Victory Cross Country Tour
Crutchfield Customer Review (What's this?)

For the size , they produce an awesome sound "quality " sound. Customer service in choosing this speaker was made easier by a caring professional agent

Pros: Expert customer service. Front speakers fit without cutting.

Cons: Rear speakers required cutting to fit

Polk DXi521

Written by: Plonk from ponte vedra beach, FL on March 25, 2016

2016 Mazda 6
Crutchfield Customer Review (What's this?)

Good quality speakers, made a big difference over the paper stock speakers in the Mazda 6.

Pros: Tight bases and smooth highs

Cons: There was not a lot of information on how to install on a new Mazda 6, so it takes a little additional fabrication on the adapter bracket supplied. Not a big deal once you figure it out. Plus there is no way to tell which stock wire is positive or negative. I had to guess, but as long as you are consistent with all 4 speakers, it does not matter.

Polk speakers

Written by: Michael P from southbridge, MA on March 22, 2016

2007 Harley Davidson Street Glide
Crutchfield Customer Review (What's this?)

I bought these Polk marine speakers for a fairing that I bought and installed on my Harley Davidson Road King, the speakers are awesome, great quality and sound fantastic. The speakers covers did not fit on the fairing because they are square so I needed to buy separate speaker grills which wasn't a big deal. Very satisfied!



Another Great Polk Product

Written by: The Bullit from Rocky Gap, VA on February 21, 2016

1994 BMW 325IS
Crutchfield Customer Review (What's this?)

Excellent Repacement Speaker for so-so factory speaker Used as replacement for kick panel speakers in a 1994 BMW 325is

Pros: Easy to Install, Fit perfectly in stock speaker position, Great sound and good looks too

Cons: None

Great buy

Written by: lvaz from New York on October 30, 2015

2013 Honda Civic SI
Crutchfield Customer Review (What's this?)

Speakers sound great and easy install.



Polk Audio DXi521

Written by: Howell from Texas on May 18, 2015

1985 Jeep CJ7
Crutchfield Customer Review (What's this?)

Outstanding sound....

Pros: Easy to install

Cons: none

Polk Audio DXi521

Written by: sgomez from New Mexico on May 10, 2015

2005 Jeep Wrangler
Crutchfield Customer Review (What's this?)

fit perfect in my 2005 Jeep Wrangler.



Truck speakers

Written by: Russ from Pittsburgh, PA on February 28, 2015

Crutchfield Customer Review (What's this?)

Needed to freshen up the speakers.

Pros: Great speaker, nice sound. Good fit. Used speaker baffles with it.

Cons: Have nothing bad to say.

Good, clear, crisp

Written by: Paul from Michigan on February 25, 2015

1979 Lincoln Continental
Crutchfield Customer Review (What's this?)

Great sounding speakers. Installed in front doors with Polk 6x9's in rear. You need some power from an amp and a good deck with equalizer to really make them come alive. Bass is a little stingy without equalization and amps. True sound does come out with the right deck and power.

Pros: Clear sounding, Very stout speakers. clear crisp highs and midrange.

Cons: Need amp and equalization to drive these.

Great for Jeep

Written by: Michael from Tuscaloosa, AL on December 18, 2014

2002 Jeep Wrangler
Crutchfield Customer Review (What's this?)

Worked great in my wifes Jeep Wrangler. Easy to install.



Trailblazer SS

Written by: EdB. from Florida Panhandle on October 29, 2014

2008 Chevrolet TrailBlazer
Crutchfield Customer Review (What's this?)

Used these Polks to replace the rear door speakers in my Trailblazer SS. Easy to install with provided instructions, although by completely removing the speaker mounting panels underneath the door panels, you can trim the mounting much more cleanly with a sabre saw, rather than trying to break off the tabs (that interfere with installation) with pliers while still in the truck. The speakers are much less efficient than the stock factory Bose speakers, by about 30 percent, which is significant. They also have a much leaner bass and midrange response, but much cleaner highs.

Pros: Cleaner, more brilliant highs.

Cons: Much less efficient than the factory Bose speakers, less bass and midrange, so overall volume for the system is reduced.

Easy install nice sound

Written by: JLmTECH from Jackson NJ on October 13, 2014

2002 Buick Century
Crutchfield Customer Review (What's this?)

Good sound. Matched them with existing Polk 6x9 in the rear deck They dropped right in to the existing OEM slots. I ent with tweeter in one unit. Did not replace the OEM tweeter in the Buick 6 speaker setup. Sound great.

Pros: Great Sound, easy install


Polk Audio Speakers

Written by: Jay B. from Southern Maryland on October 2, 2014

2007 Harley Davidson Electra Glide
Crutchfield Customer Review (What's this?)

Love the sound. Very easy to install and fits perfectly with my motorcycle.

Pros: Did not have to splice any wires and come with a how to video if I needed it.

Cons: None.

Great Speakers

Written by: Jim from New Paltz, NY on October 1, 2014

1998 Jeep Wrangler
Crutchfield Customer Review (What's this?)

Speakers sound crisp and clear at low and high volumes

Pros: Affordable, big improvement over factory speakers, easy to install instructions

Cons: Nothing to do with the product, but be patient trying to install speakers above your head in a Jeep sound bar.

2000 Jeep Wrangler

Written by: Justin from Denver, CO on September 16, 2014

2000 Jeep Wrangler
Crutchfield Customer Review (What's this?)

Overall this speaker was an improvement to the sound quality from the factory model but at 14 years old anything would have been. After being installed for one week I would say that I'm not 100% satisfied and question my purchase. I noticed the price drop over the last 6 months with these speakers and should have taken that as a warning sign.

Pros: Improvement to the clarity. Crutchfield as always is great to work with and provides everything you need to make it work. Price

Cons: Can not use the covers it comes with. Any type of bass seems washed out and dull.

Jeep Speaker Replacements

Written by: Rewards Card Reviewer from Key Largo, FL on September 9, 2014

Crutchfield Customer Review (What's this?)

All four 5.25"s swapped right into my 98 TJ, two dash and two soundbar. Crutchfield sent the appropriate wiring harnesses and 4x6 - 5.25" adapter for the dash; while nothing was needed for the soundbar, they sent two extra harnesses plus all hardware.

Pros: Everything needed, plus some Competitive price Marine grade

Cons: Polk grills didn't work out, but I don't like advertising anyway Top and doors are always off so I won't fully appreciate the sound

Good buy for the price

Written by: gunmetalRED from Toledo, OH on July 25, 2014

1998 Buick Riviera
Crutchfield Customer Review (What's this?)

I bought these to replace the blown front speakers in my '98 Buick Riviera and am quite happy with them. The materials and build quality felt very nice putting them in and they fit nice and flush under my factory grilles. They get nice and loud and remain clear even with my factory stereo. The bass response is OK, much better than other brands in this price range I have used, but I didn't expect them to be show-stoppers at this price. Great for highway cruising volume. I'll probably replace the rears with the matching 6"x9"s and I'm sure an aftermarket stereo would give them some nice punch. Great performance for a little money.

Pros: Price, build quality, clarity

Cons: None

Just As Bad as the DXi721

Written by: CQLink from Detroit on July 23, 2014

Crutchfield Customer Review (What's this?)

These speakers sound muddy and dull. I installed an Alpine KTP-445U Head Unit Power Pack and it didn't help much. These are simply poor sounding speakers with virtually no bass response. Highs don't sound much better.

Pros: None.

Cons: Dull sound even with an amplifier.

Vulcan Vaquero gets an upgrade

Written by: chuck from TN on May 20, 2014

Crutchfield Customer Review (What's this?)

These were recommended as a replacement for the factory speakers in my Kawasaki Vulcan Vaquero. The clarity has improved a lot, next will be installing an Alpine 445 amp so they can truly reach their potential. Thanks Crutchfield

Pros: Good clarity....Marine grade....awesome price

Cons: None

Polk Audio DXi521

Written by: JonathaninRichmond from Richmond, Va on April 27, 2014

2002 Dodge Caravan
Crutchfield Customer Review (What's this?)

These speakers fit my 2002 caravan great. There is a small clearance problem with the rear panel speakers which are just over the cup holders for the rear most bench. The center horn of the speaker is pressing against the plastic body panel, but we'll let time tell if that's a problem or not. The sound is great and installation was relatively simple.

Pros: Sound quality, ease of installation

Cons: Size - But that's only due to the vehicle I'm installing them on


Written by: Paul from Greencastle, IN on March 10, 2014

2000 Jeep Wrangler
Crutchfield Customer Review (What's this?)

Sounds great for my needs

Pros: Sounds great

Cons: Grills did not fit my soundbar on Jeep Wrangler. Had to use old ones.

Polk Audio DXi521 speakers

Written by: Miike from Winston-Salem, NC on January 1, 2014

2004 Jeep Wrangler
Crutchfield Customer Review (What's this?)

I'm very happy with the sound and ease of installation. The Crutchfield team was very helpful in my decision process.

Pros: They sound better than the old speakers.

Cons: I had to install said speakers myself, what a drag.

Good upgrade

Written by: Deggy from Deforest, WI on November 14, 2013

2005 Jeep Wrangler
Crutchfield Customer Review (What's this?)

I used these in the dash of my 2005 Jeep Wrangler. I had to find a special bracket to upgrade to this size (standard is 4" or 4x6). They sound great compared to stock. It powered by a Kenwood Excelon KDC-X797 CD Receiver. The upgrade in size is much better and gives better bass and treble response.

Pros: Good value. Good sound.


Happy Customer

Written by: M.E. Best from Charleston, SC on September 11, 2013

2007 Subaru Impreza 2.5i
Crutchfield Customer Review (What's this?)

These speakers compliment the Polk DXi 651 speakers I installed earlier< I am very happy with the Polk Audio products, I am certain that they will serve me very well for years to come.

Pros: Compliments my other Polk Audio speakers with quality sound at a very competitive price.

Cons: None.

Polk Audio DXi521

Written by: TimH from Ketchum, ID on August 2, 2013

2013 Ford F-150 Lariat
Crutchfield Customer Review (What's this?)

Nice little set of speakers. Well built with solid grills. I installed them in my boat with the Kenwood KMR-355U receiver unit, and am enjoying the upgrade.



Nice Sound, worth the upgrade

Written by: Mack from Harrisonburg,Va on July 27, 2013

Just purchased a 2012 Jeep Wrangler without the upgraded sound system. The stock speakers were lousy. I upgraded the speakers in the sound bar first. A week later I had to upgrade the speakers in the dash. I left the stock head unit. I put the Polk's in the front panels. Speakers sound great. No more muddy bass. The install took awhile, but that is because it is a Jeep. Sounds good with the stock head unit. Big, big difference.

Pros: Sound great. Good overall sound.

Cons: Difficult install in a 2012 Jeep Wrangler. Not the speakers fault. -- Jeeps fault.


Hands-on research

What's in the box?

Download the Polk Audio DXi521 manual

  • Two 2-way speakers
  • 2 Grilles
  • Eight 1" Self-tapping screws
  • Eight 3/8" Self-tapping screws
  • 8 Speed clips
  • Owner's Manual (English/ Spanish/ French/ German/ Italian/ Portuguese)
  • Online product registration information

Product Research


High Efficiency Design: The Polk Audio DXi Series speakers feature a high efficiency design; meaning better sound and more volume using less power.

Dynamic Balance Driver Technology: Dynamic Balance is a proprietary Polk Audio technology using laser imaging to determine what combination of speaker materials create the least amount of resonance. Eliminating resonance in speakers results in a wide, smooth response and low distortion.

Klippel Optimized Components: For a driver to reproduce complex sounds accurately, the cone must move exactly the same distance and manner in both directions. The Klippel distortion analyzer, a device that uses a laser and sophisticated software to do large-scale analysis of drivers in motion, lets Polk optimize the speaker's motor structure, voice coil alignment, and suspension to yield the best possible performance.

Composite Cones: Each speaker features a Dynamic Balance, Bi-Laminate composite, polypropylene cone woofer. These composite cones feature tremendous stiffness-to mass ratio, resulting in faster transients and finer detail.

Rubber Surrounds: For a smoother response and improved durability, the speaker uses rubber surrounds.

Aluminum Dome Tweeters: Each speaker features a 3/4" aluminum dome tweeter for clear, accurate highs. Once the speakers are mounted, the tweeters can be tilted (approximately 25°) for optimum imaging.

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.

Staff Reviews

Product reviews from the Crutchfield Labs

Four popular car speaker lines
by Robert Ferency-Viars

We listen to Alpine Type-S, Polk Audio DXi, Infinity Reference X, and Rockford Fosgate Punch car speakers in the Crutchfield Labs.

What are the Labs?
Q & A

Customer Q&A

3 questions already asked

They can be, but not recommended. The marine grade speakers have different coatings on them to help with corrosion resistance and UV exposure. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat. Hope that helps. [ Kenny  Jan 18, 2016 ]  Staff
Not sure what you mean by r type [ LARUE  Aug 02, 2015 ]
I'm sure they could be modded to be biampable, but out of the box, no. [ TOM  May 28, 2014 ]
They only have one positive and negative connection on the back for the whole speaker... There isn't a separate connection for the tweeter. Not sure if that helps or not. [ Brian  May 28, 2014 ]