About 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.
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
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
- MFR # AA3085-A
What's in the box:
Polk Audio MM840D owner's manual
- 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
Customer reviews for Polk Audio MM840D
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Average review:
4.5 out of 5 starsCustomer photos
This review was collected as part of a promotion
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More details on the Polk Audio MM840D
Features & specs
Features and Specs | ||
---|---|---|
Size | 8 -inch | |
Impedance (Ohms) | --- | |
Cone Material | Polymer | |
Surround Material | Butyl rubber | |
Port diameter (inches) | N/A | |
Port length (inches) | N/A | |
Free-Air | No | |
Dual Voice Coil | Yes | |
Sensitivity |
85 dB at 2.83 volts | |
Frequency Response | 30 - 200 Hz | |
Max RMS Power Handling | 250 | |
Peak Power Handling (Watts) | 500 | |
Top Mount Depth (inches) | 3 15/16 | |
Bottom Mount Depth (inches) | 4 11/16 | |
Cutout Diameter or Length (inches) | 7 1/8 | |
Frame Width | 8.477 | |
Frame Length | 8.477 | |
Vas (liters) | 15.8 | |
Fs (Hz) | 43 | |
Qts | 0.59 | |
Xmax (millimeters) | 20 | |
Parts Warranty | 1 Year | |
Labor Warranty | 1 Year | |
Box Requirements | ||
Ideal Sealed Box Volume (cubic feet) | 0.35 | |
Minimum Sealed Box Volume (cubic feet) | 0.28 | |
Maximum Sealed Box Volume (cubic feet) | 0.68 | |
Ideal Ported Box Volume (cubic feet) | N/A | |
Minimum Ported Box Volume (cubic feet) | N/A | |
Maximum Ported Box Volume (cubic feet) | N/A |
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.
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Customer Q&A
2 questions already asked
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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 from Gastonia, NC