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Polk Audio db840

8" Single 4 ohm Marine Certified db Series Car Subwoofer

4.7

(10 reviews)

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Specials with this product

  • Free Ground Shipping to the 48 statesdetails
  • 8" Single 4 Ohm Marine Certified Subwoofer
  • Power Handling:
    • Peak: 360 watts
    • RMS: 180 watts
  • Impedance: Single 4 ohm
  • Polypropylene cone woofer
  • Santoprene rubber surround
  • Marine certified: capable of withstanding harsh marine environment
  • Vented coil coupler
  • Fire-retardant NOMEX spider with linear motion
  • Designed and aligned with Klippel laser analyzer
  • Triple vented 4-layer Kapton single 4 ohms voice coil
  • Frequency response: 30-200 Hz
  • Sensitivity: 85 dB
  • 1-year SonicElectronix.com warranty
Product History:
Polk Audio db840 thumbnail
(newest, current model)
Polk Audio db804 thumbnail
(previous model, replaced by Polk Audio db840)
Subwoofer Specifications
Subwoofer Seriesdb Series
Subwoofer Size8"
Peak Power Handling360 watts
RMS Power Handling180 watts
Voice Coil(s)Single
Impedance (Per Voice Coil)4 ohms
Frequency Response30 - 200 Hz
Sensitivity85 dB
Xmax (millimeters)6.1 mm
Subwoofer DesignRound / Circle
Main Cone ColorBlack
Woofer CompositionPolypropylene
Woofer SurroundSantoprene Rubber
Subwoofer GrilleNo
Re-Cone Kit AvailableNo
Recommended Enclosure Specifications
Recommended Enclosure TypePorted / Vented
Sealed
Minimum Sealed Box VolumeN/A
Maximum Sealed Box VolumeN/A
Minimum Ported Box VolumeN/A
Maximum Ported Box VolumeN/A
Top-Mount Depth4"
Cutout Diameter7-1/16"
Shallow Mount InstallationNo
Warranty and Return Policy
Return Policy Standard Return Policy
Parts Warranty Duration1 year
Labor Warranty Duration1 year
Warranty ProviderSonic Electronix
Customer Review Summary for Polk Audio db840
Average Customer Rating is 4.7 out of 5 stars:
4.7
based on 10 Reviews
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Rating Distribution:
5 star:
.
.
70%
4 star:
.
.
30%
3 star:
.
0%
2 star:
.
0%
1 star:
.
0%
what's this?
Average Attributes Rating:
Durability
4.7
Value
4.8
Features
4.6
Design
4.4
Usability
4.9
what's this?
Most Helpful Customer Reviews:
May 2, 2012 Outstanding performance
Review by
Selders from Kansas City, MO
Overall
Durability
Value
Features
Design
Usability
Product was far better than the original stock woofer that it replaced, and has been solid as a rock since I installed it. Sounds great!
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May 1, 2012 Good Buy!
Review by
Cope from Atlanta, Ga
Overall
Durability
Value
Features
Design
Usability
6 months and counting. I love the fact that my db840's are marine certified because I have them in my Goldwing motorcycle and they have performed flawlessly. Can't wait to push these babies with the marine amp that I purchase.d from Sonic. The clear vocals and crisp sounds from these speakers should fair well with the 9 in sub that I also purchased from Sonics.
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October 31, 2011 Great 8
Review by
Tyler from Iron Station, NC
Overall
Durability
Value
Features
Design
Usability
This sub is perfect for anyone wantin some added bass, its got a low price point and its reasonably shallow so it wont take up too much room. Polk is a reliable brand in my opinion also.
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August 20, 2011 Excellent value, quality and sound
Review by
Rusty from Mandeville, La
Overall
Durability
Value
Features
Design
Usability
Added the Polk db840 to my golf cart sound system in conjunction with a pair of the Polk db651s. Sound from the db840 is awesome. Nice clean lows.
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August 12, 2011 Polk audio
Review by
Marco from PEORIA, AZ
Overall
Durability
Value
Features
Design
Usability
The Polk Audio works great like it a lot. Sounds great in my truck.
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View All 10 Reviews for Polk Audio db840
Speaker Wire
Choose from our recommended speaker wire to hook up your amplifier to your new subwoofer. The higher quality of speaker wire that it used for this connection, the better your subwoofer will sound.
 ProductPriceAdd?
15 ft. of 12 AWG StreetWires Speaker Wire15 ft. of 12 AWG StreetWires Speaker Wire
This SuperCable from StreetWires is a noise free link between your amplifier and your subwoofer.		$19.99
20 ft. of 12 AWG Kicker Speaker Wire20 ft. of 12 AWG Kicker Speaker Wire
Kicker uses twisted pair technology and hyper-flex cable to provide you with the cleanest sound and a simple installation.		$24.49
Sound Dampening Material
Get the most sound out of your new subwoofer with some high quality sound dampening material. It will keep the road noise out and the music inside the car.
 ProductPriceAdd?
Dynamat Rubber RollerDynamat Rubber Roller
Install your Dynamat with ease! This heavy duty rubber roller is designed specifically to install your Dynamat!		$18.99
Dynamat Xtreme Trunk KitDynamat Xtreme Trunk Kit
Get better sounding bass from your new subwoofer with enough Dynamat Extreme for your entire trunk.		$94.99
Enclosure Accessories
These accessories are designed to help you build the custom enclosure that you have always wanted, or add to the box that you already bought. Either way, these products can assist you in achieving better sound, better looks, and more bass!
 ProductPriceAdd?
20 oz. Bag of Poly-Fil20 oz. Bag of Poly-Fil
Polyester fiber fiberfill adds better bass to your system.		$5.99
16 oz. Can of Adhesive Spray16 oz. Can of Adhesive Spray
Spray adhesive used for adhering carpet to subwoofer boxes without bubbles.		$5.99
Spring Post Terminal CupSpring Post Terminal Cup
Makes adding a spring post terminal to an enclosure simple! Banana clip ready!		$2.99
Binding Post Terminal CupBinding Post Terminal Cup
Use this to easily install a binding post terminal to your subwoofer enclosure.		$2.99
Banana Clip TerminalsBanana Clip Terminals
These high grade banana clips allow you to plug into your banana clip ready terminal for a secure connection.		$4.99
System Optimization and Tuning
Use these items to assist in testing and tuning your new car audio system to perfection!
 ProductPriceAdd?
AutoSound 2000 CD-101AutoSound 2000 CD-101
Low frequency test CD		$12.99
AutoSound 2000 CD-102AutoSound 2000 CD-102
High frequency test CD specifically designed for the set-up and evaluation of sound system imaging and placement.		$12.99
AutoSound 2000 CD-103AutoSound 2000 CD-103
Audiophile reference series test disc for evaluation of all audio components.		$12.99
Main Product
 ProductPriceAdd?
Polk Audio db840Polk Audio db840$59.99

For more information on wiring subwoofers, visit our Subwoofer Wiring Guide: Subwoofer Wiring Guide

Product Summary

Manufacturer: Polk Audio
Model number: db840
UPC: 747192113766
Weight: 7.00 lbs
Internal SKU: db840
Internal product ID: 12333

Price Information

$99.99

–$40.00

$59.99

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Customer Testimonial

My order was placed on-line easily and I had my speakers in a couple of days. The service was excellent and I am amazed about how much follow up that customer service has done to make sure that my order went smoothly. Thanks for the great prices, fast shipping and excellent customer service!

- Bobby Kielbasa from Homer City, PA

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