Polk Audio db521

5-1/4" 2-way Speakers (Marine Certified)

Product videos

• Peak Power: 135W
• RMS Power: 45W
• Kapton Voice Coil Former
• ABS Grilles
• Pole Plate Heat Sink
• Stamped Steel Basket
• Frequency Response: 60-22,000 Hz

Learn more about the db521

Good news and a little bad...

This item has been discontinued

But you may be interested in the newest model that's available.

db522 thumbnail

Polk Audio DB522

OUR PRICE: $89.00

View item

Product Highlights

• Peak Power: 135W
• RMS Power: 45W
• Kapton Voice Coil Former
• ABS Grilles
• Pole Plate Heat Sink
• Stamped Steel Basket
• Frequency Response: 60-22,000 Hz


Polk Audio brand icon

Authorized dealer

Exceptional Quality and Versatility

Step up your vehicles audio performance with Polk Audio's revolutionary db521's. Cutting edge technology has allowed for an efficient speaker that has ability to accurately reproduce music like you have never heard before. A precise balance of materials including the Silk/Polymer Dome tweeter and Mica Cone woofer enable smooth roll-off and quick response at any volume. The rubber surround adds to bass response as well as increases the lifetime of the speaker under any conditions. Being marine certified, the Polk DB521's will surprise you with its versatility and ability for use in many applications. The high-efficiency loudspeaker means less power is necessary for the same quality output. The revamped db Series delivers that perfect Polk Audio performance and durability like never before.

Speaker Features:

  • 5-1/4" 2-way Speakers (Marine Certified)
  • Power Handling:
    • Peak: 275 watts per pair / 135 watts each
    • RMS: 90 watts per pair / 45 watts each
  • Impedance: 4 ohms
  • Dynamic Balance polymer/mica composite mineral filled cone is stiff yet lightweight for big sound and little distortion
  • 19mm liquid-cooled silk/polymer composite dome tweeter with neodymium magnet for clear and detailed highs
  • Low-mass 2-Layer 25mm Kapton voice coil former is lightweight for high sound output
  • Multi-hole mounting pattern and shallow depth for easy drop-in installations in most cars
  • ABS Grilles, computer optimized and based on exclusive MOMO designs
  • Durable butyl rubber surround won’t fall apart under the stress of extreme temperatures, sunlight or time
  • Pole Plate Heat Sink promotes better heat dissipation for superior power handling and reliability
  • Acoustically inert stamped steel basket
  • Flat Spider for faster, longer excursion linear motion
  • Flexible woven tinsel leads sewn directly into Spider for greater reliability
  • Frequency Response: 60-22,000 Hz
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty

Priced Per Pair

Product history:

Polk Audio DB522 thumbnail
(newest, current model)
Polk Audio db521 thumbnail
(previous model, replaced by Polk Audio DB522)
Polk Audio db525 thumbnail
(previous model, replaced by Polk Audio db521)

Specifications & Details

Speaker Specifications
Polk db Series
Priced Per
Speaker Size
2-way Coaxial
Tweeter Design
Tweeter Composition
Woofer Composition
Polymer/Mica Composite
Woofer Surround
Butyl Rubber
Peak Power Handling
135 watts
RMS Power Handling
45 watts
93 dB
Frequency Response
60 - 22000 Hz
Impedance (Per Voice Coil)
4 ohms
Shallow Mount Installation
Top-Mount Depth (Mounting Depth)
Bottom-Mount Depth
Cutout Dimensions
4-11/16 x 4-11/16 
General specifications
Speaker Grilles
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Item Details


Model Number:




Internal SKU:


Internal Product ID:


Product and How-to Videos

Customer Ratings & Reviews

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Customer Reviews

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Great Sound

I'm real happy with the quality sound these speakers put out for the cost , I'll be using the Polk Audio again . Thanks

By Melecio on October 12, 2014


found this helpful.


Sounds Amazing and works great!

By Jeff on December 8, 2011


found this helpful.

not worth the money

Installation was easy. I do NOT recommend. The speakers did not last 3 months. I don't listen to loud music but need to hear the speakers when I have the top off my Jeep. They did't sound much better than the factory speakers and one doesn't even work now.

By glen on September 28, 2011


found this helpful.

Great product

Awesome speakers. They are only 2 way so you need more to fill out a complete system. But great power with a 45w rms per channel amp. Never ran it without an amp. But sounds great.

By Bacon on March 26, 2012


found this helpful.


i bought these as replacement speakers for my TJ and could not b happier. Hooked them up to a small amp, and the sound couldnt be better for the price. and being that they are marine grade, a little splash from the hose every now and then after a little play time, wont hurt either.

By tom on May 29, 2012


found this helpful.


I purchased a new set of 4 of the 5 1/4 polk audio speakers and put them in my pontoon. The sound quality is great. I am running them off of the head unit which came with my pontoon, I am sure that they would sound even better if they were either running off of a good head unit or if amplified. I am very happy with these speakers. They sound 10 times better than the originals. Great buy!

By KEVINC on October 27, 2009


found this helpful.

Polk Speakers from now on !

I recently changed out the sound system on my 08 Harley Ultra Classic. I put in a set of the Polk db5251 components in my fairing. They sounded so clear I just knew I needed to get a set of these for my rear speaker pods. Installation was a little tricky. Thanks to Sonix and their line of spacers I got them to mount. The db521 are powered from the factory radio and the db5251's plus my Polk MM DVC 8 inch sub are being run off a rockford fosgate pbr300x4 amp. These polk speakers and subs not only surpass the Hog Tunes speakers I had they are so much clearer and put out more volume and the suckers are not even broke in yet. I now have a sound system that handles it all. Thanks again Sonix and their staff for helping me with sane pricing and great shipping.

By tj on November 7, 2011


found this helpful.

DB521 speaker

I bought these a couple of months ago to put on my motorcycle. Finally got the chance to put them on today. One, they did not fit my application (which is fine). But, I just hooked one up to see what it sounded like, and the tweeter was almost non-existant. Not good on a motorcycle with loud pipes/wind. I have some cheaper Kicker CS40 speakers on the bike now (what I could buy on short notice before a trip last year). Those sound way better! Especially, the tweeter (night & day!). I'd even cover one up, then the other. I was disappointed in the sound of these speakers. I had some Polk Audio speakers almost 30 years ago, and those things rocked. Not so much here. They were average at best. Maybe I got a bad speaker(s)? Since it didn't fit, I didn't even try the other speaker. I also bought a pair of the DB651 speakers as well.

By Dubs on April 12, 2014


found this helpful.

Not wonderful...but I didn't use them to their potential

First off I need to say that I installed these in my stock BMW. BMW uses a very low powered amp and loud tweeters. I could never really hear any difference with these Polk speakers. I believe that they would be excellent had I hooked them to an amp and disconnected the stock BMW tweeters.

By John on February 22, 2013


found this helpful.

Nice speakers

Got a pair about a week ago. Haven't hooked them up yet but just the look and feel of them make me think that they are very durable and will sound fantastic. I will repost when i install and hear them.

By Audio freak on September 25, 2012


found this helpful.


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