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Polk Audio db521

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

In Stock
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List price $109.99

You Save: $40.04 (36.40%)

$69.95

with warranty A Pair

+ FREE Shipping in US 48

Order within 18 hrs 7 mins to ship 4/2

Arrives by Tuesday, Apr. 7 to zip 07095

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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
  • 1-year SonicElectronix.com warranty

Priced Per Pair

Product History:

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

Speaker Specifications

Series
This is the manufacturer product line of speakers.
db (Polk)
Priced Per
Car Speakers are typically sold in pairs so you will receive 2 speakers for each speaker purchase on speakers marked "Priced Per Pair". If a speaker is marked "Priced Per Each" then the speaker is sold individually and each purchase you make will result in 1 speaker. High-powered tweeters, midrange and full-range pro audio for car speakers are typically sold per each speaker.
Pair
Speaker Size
Refers to the size of the speaker measured in inches. Every vehicle has standard application sizes. Please use our vehicle fitment guide for your vehicle's specific speaker sizes if you do not know them.
5-1/4"
Design
The number of individual drivers in a car speaker. Speakers with 2 drivers are known as a 2-way, and 3 drivers are known as a 3-way. Component systems are often referred to as "separates" because the tweeter is not attached to the midwoofer (main speaker driver) and mounts separately in a location such as a door post. Component systems typically come with an external crossover so you can easily adjust the high and low frequencies sent to both the midwoofer and the tweeter. Center channel speakers are great for those looking to have surround sound in their vehicle.
2-way
Tweeter Design
Designs such as cone, dome, semi-dome, balanced dome, and whizzer are most popular. Cone tweeters are simple, efficient and typically are the most reasonably priced. Dome tweeters are used in most home speakers, and provide a smoother and more accurate sound. Semi-dome design is one with a dome placed inside a cone. A Balanced dome driver is a semi-dome with equal reproduction area given the cone and dome portions of the driver. A whizzer tweeter is a separate tweeter cone driven by the voice coil of the woofer.
Dome
Tweeter Composition
Materials such as polypropylene, silk, cloth, and paper are the most common, where as many more recent tweeters are now manufactured with composites such as Aluminum, Titanium, Mylar, and other materials.

PEI is an acronym for "Polyetherimide" which is an amorphous, amber transparent, high-performance thermoplastic.

Silk
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.
Polymer/Mica Composite
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.
Butyl Rubber
Peak Power Handling
Peak power handling refers to the amount of power a speaker can handle during a brief musical burst. The RMS power range figure is a much more reliable rating for determining the speaker's power requirements. The Peak power handling specification is typically rated per speaker unless otherwise noted.
135 watts
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.
45 watts
Sensitivity
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".
93 dB
Frequency Response
The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
60 - 22000 Hz
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
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.

Yes
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.
2-5/16"
Bottom-Mount Depth
The depth when installed from the bottom of the mounting surface. Measured from the bottom of the speaker's magnet to the top of the mounting holes on the rim of the speaker.
2-7/16"
Cutout Dimensions
Refers to the dimensions of the hole, measured in inches or millimeters, required to contain the speaker.
4-11/16 x 4-11/16 
Speaker Grilles
A grating or screen of metal or plastic bars or wires, mounted in front of a speaker as protection. If yes, the speakers will include matching speaker grilles. If no, there are no grilles included.
Yes

Warranty and Return Policy

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

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
70%
4 Star
20%
3 Star
3%
2 Star
3%
1 Star
5%

Average Attribution Rating

Durability
4.6
Value
4.6
Features
4.4
Design
4.6
Usability
4.7
glen

Mandeville, LA

Overall
Durability
Value
Features
Design
Usability
not worth the money

September 28, 2011

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.

17 of 24 found this helpful

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tom

indiana

Overall
Durability
Value
Features
Design
Usability
perfect!!!

May 29, 2012

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.

18 of 29 found this helpful

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Melecio

San Antonio, TX

Overall
Durability
Value
Features
Design
Usability
Great Sound

October 12, 2014

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

17 of 28 found this helpful

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Jeff

Chino CA

Overall
Durability
Value
Features
Design
Usability
Great

December 8, 2011

Sounds Amazing and works great!

17 of 29 found this helpful

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John

Edmonds, Washington

Overall
Durability
Value
Features
Design
Usability
Not wonderful...but I didn't use them to their potential

February 22, 2013

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.

13 of 23 found this helpful

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Audio freak

Candler, NC

Overall
Durability
Value
Features
Design
Usability
Nice speakers

September 25, 2012

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.

13 of 23 found this helpful

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Bacon

Nj

Overall
Durability
Value
Features
Design
Usability
Great product

March 26, 2012

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.

13 of 23 found this helpful

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Capman

Smyrna, TN

Overall
Durability
Value
Features
Design
Usability
Excellent product

April 1, 2011

I am running these with a Sony CDX M60UI, a pair of db651s and a Bazooka 8" passive sub. The sound is wonderful. Very crisp highs and soft lows. I have heard that they sound even better with an amp. Not much room in my little boat to mount an amp, but these sound so good, I really don't need one. With a 93dB sensitivity rating, a few watts will give you great sound. I would recommend these to anyone.

10 of 18 found this helpful

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John

WWoodridge, IL

Overall
Durability
Value
Features
Design
Usability
Polk DB-521

October 2, 2014

I purchased these speakers for motorcycle use. Very happy with the increased clarity and volume over the OEM speakers. Upgraded the speakers from OEM and did not install an amp. I am sure the next move is to bring more out of these speakers by installing an amp.

8 of 15 found this helpful

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NorthernDad

Canada

Overall
Durability
Value
Features
Design
Usability
Nice sound, but not much bass

October 24, 2011

Got these speakers to replace stock kia speakers. Ended up keeping the stock speakers because these ones have terrible bass output. They were great for full range, almost making music sound 'live' - everything was good but the bass, so they had to go.

9 of 17 found this helpful

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lalsr

hunlock creek pa

Overall
Durability
Value
Features
Design
Usability
great deal

October 19, 2011

Plain and simple. Just a great speaker. I used them on my motorcycle fairing. I used 4 speakers with a jvc power unit cd player and being they are marine grade i don't worry about the rain.

8 of 15 found this helpful

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KEVINC

LAKE JAMES, IN

Overall
Durability
Value
Features
Design
Usability
POLK AUDIO SPEAKERS

October 27, 2009

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!

3 of 5 found this helpful

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michael

Tamaqua, PA

Overall
Durability
Value
Features
Design
Usability
great speakers!

April 30, 2008

these are awesome, they are great no distortion, handle the bass from the the headunit power, if you amp them i recommend bassblockers though, mine didnt distort but at high volume in my blazer its so loud you probably couldnt tell. great SQ and very nice vocals! good buy!

1 of 1 found this helpful

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Fred

Midland mi

Overall
Durability
Value
Features
Design
Usability
Great product great service

March 9, 2015

This is the second set of Polk speakers I have purchased. I simply love the sound and quality!

0 of 0 found this helpful

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Dubs

Ankeny, IA

Overall
Durability
Value
Features
Design
Usability
DB521 speaker

April 12, 2014

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.

11 of 22 found this helpful

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Joe

Indianapolis, IN

Overall
Durability
Value
Features
Design
Usability
Get the 6.5 if you can instead

September 19, 2012

While these 5.25" speakers do sound great, I mean really good for their size, the 6.5" sound twice as good if not more. I am running 4 of these 5.25" and 2x 6.5", and a 12" MTX sub, powered by a 6 channel MBQuart amp. The 6.5" are what make this system and if I was just running 4 of them, it would sound much better than the 4 x 5.25" and 2 x 6.5". They are much louder, have mid range base, and just a cleaner sound. If all you can fit are these 5.25" then go for them, they do sound great and are only beat by JLAudio of the same size. These POLKS are amazing speakers.

9 of 18 found this helpful

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Curtis

Walnut Creek, CA

Overall
Durability
Value
Features
Design
Usability
Great Speakers!

January 30, 2012

These are one of the best speakers you can buy without getting into components or needing to run an amp to them to make them loud. They are very crisp and have no distortion when the music is up louder. I would definitely buy these speakers again.

3 of 6 found this helpful

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tj

Cuyahoga Falls, OH

Overall
Durability
Value
Features
Design
Usability
Polk Speakers from now on !

November 7, 2011

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.

12 of 24 found this helpful

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Jaime

Summit, NJ

Overall
Durability
Value
Features
Design
Usability
Hhighly reconnnmended!!

July 3, 2011

I got these for my freightliner rig, man, these are very good!! Had to amped them.

8 of 16 found this helpful

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loren

edgewater,fl

Overall
Durability
Value
Features
Design
Usability
great value

March 4, 2011

Looks and sounds great on my motorcycle

2 of 4 found this helpful

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Accessory Tools and Products

Accessories added

Streetwires 50 ft. of True Spec 16 Gauge Speaker Wire

You need speaker wire to connect your speakers!

Your Price $29.99

16-14 AWG Butt Connectors

These blue butt connectors are ideal when connecting thicker speaker wire your new aftermarket speakers!

Your Price $4.99

16-14 AWG Blue T-Tap Adapters

Allows for fast and easy splicing of wires by easily tapping into the cable.

Your Price $4.49

16-14 AWG Quick Disconnect Connectors

These blue quick disconnect connectors make it easy to connect and disconnect speaker wire your to your new aftermarket speakers!

Your Price $7.99

NVX SDSK2 Speaker Kit

Eliminates speaker panel distortion and reduces vibration, rattles, and squeaks!

Your Price $14.99

Dynamat Xtreme Speaker Kit 10415

Enough sound dampening for 2 speakers!

Your Price $17.95

Stinger Roadkill Speaker Kit

Use this to eliminate rattle from your speakers!

Your Price $13.99

Car Stereo and Speaker Installation Tool Kit

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

Your Price $16.99

Universal Wire Puller & Grabber

Running wires has never been easier! This wire puller allows you to run wires through those hard to reach places!

Your Price $6.99

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

Xscorpion WDCR2 Window and Door Clip Remover

Removes and installs handle and window crank clips.

Your Price $6.99

NVX SDRLR1 Sound Dampening Rubber Roller

Install your Sound Dampening with ease! This heavy duty rubber roller is designed specifically to install your NVX products!

Your Price $7.99

Speaker Baffles for your Speakers

Enhance the sound of your speakers with these easy to install speaker baffles.

Your Price $9.99

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Browse 1 question and 9 answers
Hide answersShow all answers | Sort by
Why did you choose this?
Sonic Electronix Store
research has showed these are the best you can get.
Tracy B on Feb 11, 2015
I am using these speakers in a motorcycle application so being marine cert and based on using Polk in the past. The speakers just work sound great
Phil T on Nov 3, 2014
indian motorcycle forum said great forprice
nicola p on Nov 26, 2014
High quality speakers that fit the fairing of an Indian Chieftain motorcycle.
Dan O on Sep 4, 2014

Product Summary

Manufacturer

Model Number

db521

UPC

747192112769

Weight

4.50lbs

Internal SKU

db521

Internal Product ID

9124

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: Polk Audio db521

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