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Polk Audio MM840D

Mobile Monitor Series 8" sub with dual 4-ohm voice coils

10 Reviews | 2 questions - 2 answers

Item # 107MM840D

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Polk Audio MM 842 DVC

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Overview

Our take on the Polk Audio MM840D

Polk Audio's Mobile Monitor Series subwoofers bring out superior performance from lighter materials, so you'll get the impact you want without the extra weight of a conventional system. Advanced engineering and optimized components reproduce your sound with uncompromising accuracy, for low end that is rich and clear.

Polk Audio's Mobile Monitor Series subwoofers bring out superior performance from lighter materials, so you'll get the impact you want without the extra weight of a conventional system. Advanced engineering and optimized components reproduce your sound with uncompromising accuracy, for low end that is rich and clear.

The MM840D 8" dual voice coil subwoofer handles up to 250 watts RMS. A copper voice coil and neodymium magnet motor drive the polymer cone with exceptional efficiency. The carbon composite basket features a "wagon wheel" design that resists flexing during heavy excursion, so your sub hits solidly without distorting. Dual 4-ohm voice coils offer options for wiring a multi-sub system or drawing maximum power from your mono amplifier.

This sub is certified for marine use, and Polk includes corrosion-resistant stainless steel mounting hardware.


Priced per speaker

Awesome Sub! DVC and solid performer even at 8 inches! grills are a bit tough to find but have found a great metal aftermarket that works great.

Scott, Gastonia, NC

What's in the Box:

  • One 8" dual voice coil subwoofer
  • 1 Foam gasket
  • Eight 1-1/2" Allen head self-tapping screws
  • 8 Speed clips
  • Owner's Manual (English/ French/ Spanish/ German/ Italian/ Portuguese)
  • Online registration sheet

Product Highlights:

  • 8" subwoofer with dual 4-ohm voice coils
  • polymer cone with butyl rubber surround
  • carbon composite basket
  • certified for marine use
  • optional matching grille complements the basket design
  • power range: 100-250 watts RMS (125 watts RMS per coil)
  • peak power handling: 500 watts
  • frequency response: 30-200 Hz
  • sensitivity: 85 dB
  • top-mount depth: 3-15/16"
  • sealed box volume: 0.35 cubic feet
  • warranty: 1 year
  • Our 60-day money-back guarantee
Reviews

Polk Audio MM840D Reviews

Average Customer Review(s):

(10 Reviews)
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Details

Hands-on research

Product Research

Features
Enclosure Compatibility

Features

Basket: The MM Series subwoofers use high-tech carbon composite basket structures for light weight and maximum rigidity. They will not rust or flex like stamped steel designs.

Materials: The new polymer woofer cone and butyl rubber surround will not break down over time and will survive the rigors of harsh automotive environments.

Dual Voice Coils: The high temperature, 1-1/2" diameter copper voice coils and polyamide former withstand the most rigorous use while maintaining extremely low distortion. The MM840DVC features dual 4-ohm voice coils; when wired in parallel the subwoofer presents a 2-ohm load, when wired in series the subwoofer presents an 8-ohm load.

Terminals: The woofer has heavy duty spring terminals that will accept single banana plugs, pin connectors, and bare wire up to 8 gauge.

Marine Certified: Polk MM Series speakers are built to withstand exposure to moisture and UV rays, so they work well in boats and cars.

Klippel Measurement Technology: State-of-the-art laser based Klippel measurement technology is used to optimize the woofer's motor structure, voice coil alignment, and suspension to improve performance, even at extreme listening levels.

Enclosure Compatibility

Sealed Box Volume: Polk recommends using this woofer in a sealed enclosure; the ideal internal volume is 0.35 cubic feet.

Our Product Research Team

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Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

polk audio componets have always performed great for me [ john  Mar 30, 2017 ]
I have been a Polk Audio fan for several years. It's been a long time since I put a system together and this will probably be my last, it was Polk or nothing... [ Gregory  Mar 24, 2017 ]
product is supposed to be able to withstand additional environmental abuse (and will pair nicely with my soundstream nano amp power wise), since I will be using in an offroad desert truck that will constantly be jarred and vibrated to death. :) Plus, it fits in the stock mounting location of factory one. :) [ Ryan  Mar 18, 2017 ]
Needed a small sub for a utv to mach a set of mm series 5.25". To bad they don't make the mm series any more, they are awesome. [ Danen  Mar 10, 2017 ]
Specs were better than most shallow mounts, which is what I had to use in my regular cab ranger. Xmax was higher and required less space (.35 cu ft) compared to most that are around half a cubic foot. [ MATTHEW J  Jan 23, 2017 ]
I like the sound [ Adam  Dec 25, 2016 ]
Dual Voice Coil and high sensitivity and along with a good history based product [ Brian  Nov 06, 2016 ]
Price [ raymond  Aug 10, 2016 ]

2 questions already asked

Thanks for your question. It's almost an inch. 0.95" to be exact. Hope this information helps. [ Kenny  Jan 21, 2017 ]  Staff
Thanks for your question. Weight is 9.5 pounds. Hope that helps. [ Kenny  Nov 29, 2016 ]  Staff
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