Skip Navigation

Polk Audio MM5251

5-1/4" component speaker system

6 Reviews | 1 question - 1 answer

Find what fits your vehicle

Can't find your exact vehicle?

Item # 107MM5251

This item is no longer available.

Shop all Component Speakers

Overview

Our take on the Polk Audio MM5251

Polk Audio continues its tradition of making brilliant-sounding speakers in stylishly designed packages — their Mobile Monitor (MM) Series speakers look great and sound even better. Each speaker utilizes an extra-strong, extra-small neodymium magnet that saves space and weight, allowing these speakers to fit into more places in more vehicles while still delivering a full sound with lots of kick. Their lightweight carbon composite frames provide strong, flex-free support for the speakers' motor assemblies.

Polk Audio continues its tradition of making brilliant-sounding speakers in stylishly designed packages — their Mobile Monitor (MM) Series speakers look great and sound even better. Each speaker utilizes an extra-strong, extra-small neodymium magnet that saves space and weight, allowing these speakers to fit into more places in more vehicles while still delivering a full sound with lots of kick. Their lightweight carbon composite frames provide strong, flex-free support for the speakers' motor assemblies.

The Polk MM5251 component system features 5-1/4" woofers with honeycomb-textured woven glass fiber composite cones that respond very quickly for a clean, crisp, and powerful sound. Large voice coils — over an inch in diameter — give the speaker high power handling capability and extended reliability.

Separate 1" silk dome tweeters add a sweet high end that blends perfectly with the low notes, and swivel mounts let you aim the tweeters to produce a superior soundstage in your car. The external crossovers direct the signal flow so all your music stays in perfect harmonic balance, from the fat thump of an electric bass all the way up to the "ping" of the cymbals. A tweeter attenuation setting allows you to tweak the high-frequency level to your taste.

Important Note: These Polk speakers use a low-impedance design to pull more power safely from your car stereo or amplifier. This design is compatible with virtually all factory and aftermarket stereos.

These speakers sound great together, I matched them up with a alpine amp and they sound so nice. Great improvement over the stock system in my car

Kyle, Wakefield, MA

What's in the Box:

  • Two 5.25" woofers
  • 2 Grilles
  • Two 1.0" tweeters (each tweeter has attached 18" speaker leads)
  • 2 Flush-mount cups
  • 2 Metal flush-mount clamps
  • 2 Surface-mount cups
  • 2 Crossovers
  • Two 41" lengths of speaker wire (each length of wire has female quick-slides on one end and tinned wire on the other end)
  • Two 39" lengths of speaker wire (each length of wire has male quick-slides on one end and tinned wire on the other end)
  • 10 Phillips-head screws
  • 8 Hex-head screws
  • 8 Speed clips
  • Owner's Manual (Eng/Span/Fren/Ger/Ita/Port)
  • Online registration sheet

Product Highlights:

  • component speaker system includes two 5-1/4" woofers, 2 tweeters, and two external crossovers
  • woven honeycomb glass fiber composite woofer cone with butyl rubber surround
  • 1" silk composite dome tweeter with swivel mount
  • 2-way external crossover with 2-position tweeter level
  • certified for marine use
  • 2.7-ohm impedance for extra power (compatible with virtually all factory or aftermarket car stereos)
  • power range: 15-90 watts RMS (200 watts peak power)
  • frequency response: 50-25,000 Hz
  • sensitivity: 92 dB @ 2.83 V
  • top-mount depth: 2-3/8"
  • warranty: 1 year
  • Our 60-day money-back guarantee
Reviews

Polk Audio MM5251 Reviews

Average Customer Review(s):

(6 Reviews)
rewards card

Submit a review and enter to win a $350 rewards card

Review this product

Thanks for submitting your review

Most reviews are processed and published within 5 business days. You will receive a confirmation email once your review has been published.

Your Review

Use the stars below to rate the overall product on a scale of 1-5
1500
Upload your photos

Not visible. Email associated with order.
(e.g., Charlottesville, VA)

Additional Fields (optional)

500
500

By submitting this review, you agree to our terms and review guidelines.

Filter by rating

Customer photos


<< >>
Details

Hands-on research

Features and Specs

General
Speaker Size 5 1/4
Design 2-way
Tweeter Design 1" Dome
Tweeter Composition Silk/polymer composite
Woofer Composition Glass Fiber Composite
Woofer Surround Butyl Rubber
Parts Warranty 1 Year
Labor Warranty 1 Year
Specifications
Sensitivity (1W at 1 meter) 92
Sensitivity at 2.83 volts N/A
Frequency Response 50 - 25k Hz
Minimum RMS Wattage 15
Maximum RMS Wattage 90
Peak Power Handling (Watts) 200
Impedance (Ohms) 3
Top-mount Depth (Inches) 2 3/8
Bottom-mount Depth (Inches) N/A
Cutout Diameter or Length (inches) 4 5/8

Product Research

Woofers
Tweeters
Crossovers

Woofers

Dynamic Balance: Dynamic Balance is a proprietary Polk Audio technology using laser imaging to determine what combination of speaker materials create the least amount of resonance. Eliminating resonance in speakers results in a wide, smooth response and low distortion.

Klippel Optimized Components: Using a state-of-the-art Klippel Distortion Analyzer, Polk 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.

Woofer Cones: Woven glass composite cones feature tremendous stiffness-to-mass ratio. Lower mass means faster transients and finer detail.

Butyl Rubber Surrounds: For a smoother response and improved durability, the woofers use butyl rubber surrounds. The airtight rubber surrounds stand up to moisture, sunlight and extreme temperatures while allowing long excursion linear motion and years of reliable use.

Neodymium Magnets: The speaker's neodymium magnets offer exceptional strength to performance ratio and is extremely lightweight.

Large Diameter Voice Coils: Large diameter, 30mm voice coils increase the speaker's reliability and power handling capacity.

Space Age Materials: Space Age Materials reduce weight of components while offering rock solid reliability, advanced looks and ultra high performance.

Carbon Composite Basket: The speaker's carbon composite basket is lightweight and will not flex during music audio peaks.

Grilles: Strong ABS plastic grilles are included. These computer optimized grilles feature a spoke-wheel design.

Mounting: The speaker itself has 4 mounting holes for a standard 5-1/4" application.

Marine Certified Woofer: Polk MM Series speakers are built to withstand exposure to moisture and UV rays, so they work well in boats and cars. They also include stainless mounting hardware for corrosion and rust resistance.

Tweeters

Silk/Polymer Composite Tweeters: The 1" liquid-cooled, silk/polymer composite soft-dome tweeters provide clear, detailed highs.

Mounting: The supplied mounting cups allow you to surface- or flush-mount the tweeters. The tweeters swivel in the flush-mount housings, allowing you to adjust them for optimum imaging.

Tweeter Mounting Dimensions:

  Surface Mount Flush Mount
Mounting Height 1.065" 0.425"
Depth 0.625" (screw depth) 0.865"
Frame Diameter 1.995" 2.295"
Cutout Diameter   N/A 1.945"

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

Crossovers

2-Way Crossovers: The MM5251 features two 2-way external crossovers with a 2-position tweeter level.

Tweeter Attenuation Switch: You can adjust the output of the tweeter to match a level appropriate to your vehicle or your system. On one side of the crossover, the tweeter attenuation switch can be set to 0dB or -3dB.

Electronic Tweeter Protection Circuits: Each crossover has a built-in protection circuit that guards the tweeter against accidental damage from high power.

Crossover Connections: The crossover inputs and outputs are screw terminals. The crossover housing is vented for adequate heat dissipation.

Mounting: There are two mounting holes in the base of each crossover.

Crossover Dimensions: Width = 4.25", Height = 1.25", Depth = 3.5265"

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 verify what’s in the box, 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.

Accessories
Q & A

Customer Q&A

1 question already asked

This will depend largely on your vehicle. For details on installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on what you will need for an installation. [ Kenny  Jun 03, 2016 ]  Staff
Articles