Our Product Research Team
At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere.
That's because we have our own in-house Product Research team — they open the box,
verify contents, check the owner's manual, and record dimensions, features and specs.
We stay on top of new products and technologies to help people make informed choices.
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.
Sealed Box Volume: Polk recommends using this woofer
in a sealed enclosure; the ideal internal volume is 0.35 cubic feet.