Polk Audio MM521 5.25” Coaxial Speakers



Whether you’re into four-wheeling, two-wheeling, hot-rodding, or just a leisurely drive, you’ll find no better way to enjoy your music on the road, or off-Road, than with Polk Audio MM521 5.25″ Coaxial speakers.





Polk Audio MM521 – 5.25” Coaxial Speakers

Through the use of high-tech carbon composite baskets, powerful neodymium motor structures using oversized voice coils, and state-of-the-art woven glass composite cones, Polk Audio offer high-end audio performance normally found only in the most expensive loudspeaker systems.

In addition, these space age materials offer weight savings that can mean higher performance for your car or boat.

Don’t settle for factory-installed sound!


  • Polk Audio use space age materials reduce weight of components while offering rock solid reliability, advanced looks and ultra high performance.
  • Neodymium magnets a rare earth metal offering exceptional strength to performance ratio, found only in the most exotic speakers, saves tremendous weight. Don’t let the sound system weigh your vehicle down. Since the magnet is smaller, the speaker can fit into more applications.
  • Carbon composite basket based on the spokes of a wheel is lightweight, will not flex during peaks and looks great! Don’t be afraid to show off the back of your speaker.
  • Woven glass composite cones feature tremendous stiffness-to mass ratio. Lower mass means faster transients and finer detail.
  • Klippel optimized components using a state-of-the-art Klippel distortion analyzer, Polk Audio engineers were able to optimize the woofer’s motor structure, voice coil alignment and suspension for the best possible performance, even at extreme listening levels.
  • Large-diameter voice coils (30mm) in drivers increase reliability and power handling capacity.
  • Swivel mount tweeters allow precise aiming of sound.
  • Stylish grille is included.

All PolkAudio  products are made using the best materials and the most advanced manufacturing techniques.

They pass the industry’s most exhaustive quality tests, including drop testing, extreme signal response and UV & salt exposure testing.

Polk Audio loudspeakers are built to perform for a lifetime.