Garage
Shop

Polk Audio Mobile Monitor 5.25" + 6"x9" Speakers Combo

MM521 5.25" 2-way Mobile Monitor Series Coaxial Speakers + MM691 6"x9" 3-Way Mobile Monitor MM Series Coaxial Speakers

Product videos
highlight-star-icon

• Peak Power: 200W
• RMS Power: 90W
• 2-way Marine Certified Coaxial Speakers
• Woven glass composite cone woofer
• Butyl rubber surround for a smoother response
• 1" Silk/Polymer composite swivel tweeter
• Klippel optimized components for distortion-free sound

Learn more about the mm521_mm691

We apologize

This item has been discontinued

Product Highlights


• Peak Power: 200W
• RMS Power: 90W
• 2-way Marine Certified Coaxial Speakers
• Woven glass composite cone woofer
• Butyl rubber surround for a smoother response
• 1" Silk/Polymer composite swivel tweeter
• Klippel optimized components for distortion-free sound

Description


Polk Audio brand icon

Authorized dealer

MM521 fit most 6x9" and 5x7"/6x8" locations,
with appropriate speaker adapter. Click "Related Items" Tab.

MM Series Superior Performance

The Mobile Monitor Series by Polk Audio is the result of 3 years of research and development. The series uses high quality materials and the newest loudspeaker technology to bring the listener an unforgettable experience. The best part about the MM Series is the affordable price.

Polk Audio MM521

5.25" 2-way Mobile Monitor Series Coaxial Speakers (Marine Certified)
Quantity: 1 Pair

General Features

  • 5-1/4" 2-way MM Series Marine Certified Coaxial Speakers
  • Power Handling:
    • Peak: 400 watts per pair / 200 watts each
    • RMS: 180 watts per pair / 90 watts each
  • Woven glass composite cone woofer
  • Butyl rubber surround for a smoother response
  • 1" Silk/Polymer composite swivel tweeter
  • Klippel optimized components for distortion-free sound
  • 2.7 ohms impedance
  • 25mm Large diameter voice coil increase reliability
  • Carbon composite basket
  • Neodymium magnet structure for more power
  • Top-mount depth: 2-1/2"
  • 1-year SonicElectronix.com warranty

Polk Audio MM691

6x9" 3-Way Mobile Monitor MM Series Coaxial Speakers (Marine Certified)
Quantity: 1 Pair

General Features

  • 6" x 9" Mobile Monitor MM Series 3-way Marine Certified Speakers
  • Power Handling:
    • Peak: 600 watts per pair / 300 watts each
    • RMS: 250 watts per pair / 125 watts each
  • Recommended power range: 15 - 125 watts RMS per channel
  • Woven glass composite cone woofer
  • Butyl rubber surround
  • 1" Silk composite dome tweeter
  • 3/4" Super tweeter
  • 2.7 ohms impedance
  • Klippel distortion analyzer
  • 1-1/4" (30mm) Large diameter voice coil
  • Neodymium magnet structure
  • Top-mount depth: 3-3/16"
  • Grille Included
  • 1-year SonicElectronix.com warranty

Important Note: Polk Audio specifies the nominal impedance of these speakers to be 2.7 ohms. The product box states the impedance to be 4 ohms and the speaker magnet shows 2 ohms, this has been confirmed by Polk Audio to be an incorrect specification. The product manual is correct in stating the nominal impedance of the MM series of speakers to be 2.7 ohms.

Specifications & Details


Front Speaker Specifications
Speaker Size
5-1/4"
Design
2-way Coaxial
Shallow Mount Installation
No
Tweeter Design
Dome
Tweeter Composition
Silk-Polymer Composite
Woofer Composition
Woven Glass Fiber
Woofer Surround
Butyl Rubber
Peak Power Handling
200 watts
RMS Power Handling
90 watts
Sensitivity
92 dB
Frequency Response
50 - 25000 Hz
Impedance (Per Voice Coil)
2.7
Top-Mount Depth (Mounting Depth)
2-1/2"
Cutout Dimensions
4-11/16 x 4-11/16 
Speaker Grilles
Yes
Rear Speaker Specifications
Speaker Size (Rear)
6" x 9"
Design
3-way
Shallow Mount Installation
No
Tweeter Design
Dome
Tweeter Composition
Silk
Woofer Composition
Woven Glass Fiber
Woofer Surround
Butyl Rubber
Peak Power Handling
300 watts
RMS Power Handling
125 watts
Sensitivity
94 dB
Frequency Response
30 - 25000 Hz
Impedance (per voice coil)
2.7
Top Mount Depth
3-3/16"
Cutout Dimensions
5-1/2 x 8-3/8 
Speaker Grilles
Yes
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Sonic Electronix

Item Details


Manufacturer:

Model Number:

MM521_MM691

Weight:

12.00lbs

Internal SKU:

mm521_mm691

Internal Product ID:

105411

Product and How-to Videos


Customer Ratings & Reviews



5 star
80%
4 star
20%
3 star
0%
2 star
0%
1 star
0%



Durability
4.8
Value
4.8
Features
4.8
Design
4.9
Usability
4.8

Customer Reviews

Sort by:

Loading...

talk about bang for your buck

The following review is for MM691, which is a part of the bundle you are viewing.

hesitant at first but once i put them next to my type x pros i was relieved. Not only can the keep up but they can outdo them and the price is definitely a nice perk too.

By iceman on March 27, 2010

65

found this helpful.

Great sounding speaker

The following review is for MM521, which is a part of the bundle you are viewing.

Overall this speaker has a nice warm sound that gets better and better. I have only had these for a week and they get better bass extension, although it isnt completely needed because I have a sub. I purchased these the 6.5 components, and the 6x9 polks as well they sound great together. I have a 12 inch kicker L7 solobaric and these speakers keep up the bass doesnt over power them.

Pros Great customer service and quick shipping clean sound, with crisp not overall bright highs perfect sounding.

Cons: none really they sound great

By michael on April 21, 2009

68

found this helpful.

I think I'm gonna need a bigger AMP

The following review is for MM691, which is a part of the bundle you are viewing.

Replaced 2 Sony Xplod with these and wow what a difference.. these Monsters hits hard.. Now I get a nice clean mid bass and the highs are very clear..

I have a Clarion EQ hooked up to my Pioneer gm6400 just for the 6x9 and I had to turn all the levels back to 0. Unfortunately my amp is only 75w rms at 2ohms x 4 (2channels bridged for a 10" sub) so I have to upgrade my Amp since I cant crank up the volume..My rear deck now rattles so it now its also a Dynamat project..

These speakers brought out things I have not experienced before with my Sonys good and bad ;)
Definitely recommend these speakers to anyone but be aware the thin metal on the rear deck will shake so please use sound deadening material.
By the way C********** stated these won't fit my 07 Altima but the DB691 would.

Maybe because these are rated at 2.7 ohms? But they fit perfectly no mods, brackets etc just can't use the Polk grills..

By Jovan on October 27, 2010

63

found this helpful.

good product

The following review is for MM691, which is a part of the bundle you are viewing.

I recommend this product,sounds good and easy installation

By prez on November 15, 2009

62

found this helpful.

Great Clarity

The following review is for MM691, which is a part of the bundle you are viewing.

Great speakers that allow you to crank it up inside without blasting out the neighbors. You can definitely hear me coming but you don't hear the annoying rattling that most speakers generate. These speakers are with out a doubt the best bang for the buck!

By keith on December 20, 2010

62

found this helpful.

Polk MM521

The following review is for MM521, which is a part of the bundle you are viewing.

I put these in my 2006 Harley Davidson Electra Glide Classic running the stock radio w/o an amp. They are a huge improvement over stock, and have amazing clarity and bass. They do get louder with use. I had to ziptie the crossovers to the fairing supports, which was no problem. I had to remove the little speaker covers, but the speakers look cool. I've washed the bike and they've been wet several times with no issues. I may try a small amp with them for more sound and clarity at speed! Highly recommend!

By RJW on November 17, 2010

65

found this helpful.

not bad.

The following review is for MM691, which is a part of the bundle you are viewing.

These speaker's aren't to bad, I think my jl audio speakers that I had previous to these mm's sound better at extreme volume.

By D on January 11, 2015

59

found this helpful.

Polk Audio MM521 Speakers

The following review is for MM521, which is a part of the bundle you are viewing.

I have used many brand marine stereo speakers and these are by far the best sounding speakers that I have used. Have installed about 300 stereos in golf carts and now this is the only speaker that I use.

By UniqueCarts on May 30, 2014

64

found this helpful.

Polk Audio MM691

The following review is for MM691, which is a part of the bundle you are viewing.

Great speakers. good ammount of bass, and decent mids and highs. would reccomend to others.

By Gerald on September 14, 2011

60

found this helpful.

MM521 = Great speakers.

The following review is for MM521, which is a part of the bundle you are viewing.

I have these speakers in the fairing on my motorcycle. I have not heard better sounding 5-1/4" or smaller speakers. They play loud and clear, with great highs, and surprisingly good bass. They far surpass the stock speakers. Plus, they are waterproof.

By nunyo on August 9, 2010

67

found this helpful.

Add-ons


Related Products

This item is frequently compared to these items

Scosche SA68

• The SA68 speaker adapters fit most aftermarket 5 1/4" and 6 1/2" speakers into a 6" x 8" factory opening
• Compatible with Vehicles

(35)

$7.99

Metra 82-5600

• 5 1/4" / 6-1/2 Component/Coaxial Speaker to 6" x 8" Adapter
• Works with 6.5" Speakers
• Installs in 5x7" and 6x8" Locations
• Compatible with select 1991-1996 vehicles from Ford, Mercury, Lincoln Vehicles

(3)

$12.99

Metra 82-6901

• 5-1/4" or 6-1/2" Speaker to 6" x 9" Mounting Hole Adapters
• Mount your pair of 5-1/4" or 6-1/2" speakers in a 6" x 9" mounting hole

(30)

$14.99

Scosche SA69

• The SA69 speaker adapters fit most aftermarket 5 1/4" and 6 1/2" speakers into 6 x 9" factory openings

(34)

$14.95

Related Searches


MM521_MM691 small

Item added to your cart.

Price: $239.90

Essential add-ons
Five Piece Installer's Panel Removal Tool Kit

Helps with removing dash and trim panels during installation.

$18.99

$11.99

Add to cart
18 Butt Connectors, 2 Ring Terminals, and Zip Ties

Great for connecting your car stereo wires to the harness

$9.95

$9.95

Add to cart
NVX XBG3PK Big 3 Kit with True 0 Gauge 100% Oxygen-Free Copper

1/0 AWG Big 3 Upgrade Kit with 100% OFC Wire for Audio Sytems up to 350 Amps

$114.99

$99.99

Add to cart
Save up to 10 different vehicles in your garage

Loading...
Identify your vehicle and submodel details
  • Owner’s manual
  • Vehicle’s insurance card
  • Vehicle registration
  • Vehicle produced after 2005: Inside driver’s side door
  • Vehicle produced before 2005: Rear passenger doorjamb, glove box, center console, or engine compartment
Car Info Side Door Icon
Vehicle Registration Icon
Vehicle Insurance Icon