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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

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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

$309.90

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Scosche TK12 Car Stereo Installation Kit

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$18.99

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Kicker Big 3 Package 1/0 Gauge Big 3 Upgrade Kit

This Big 3 Kit features HyperFlex cable and comes with everything you need to upgrade your factory power and ground wire.

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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.

Front Speaker Specifications

Speaker Size
Refers to the size of the speaker measured in inches. Every vehicle has standard application sizes. Please use our vehicle fitment guide for your vehicle's specific speaker sizes if you do not know them.
5-1/4"
Design
The number of individual drivers in a car speaker. Speakers with 2 drivers are known as a 2-way, and 3 drivers are known as a 3-way. Component systems are often referred to as "separates" because the tweeter is not attached to the midwoofer (main speaker driver) and mounts separately in a location such as a door post. Component systems typically come with an external crossover so you can easily adjust the high and low frequencies sent to both the midwoofer and the tweeter. Center channel speakers are great for those looking to have surround sound in their vehicle.
2-way
Shallow Mount Installation
This means that the subwoofer/speaker is designed to be installed in areas that do not have a lot of space. Shallow mount subwoofers are typically found under a seat or behind the seat in some trucks.

Shallow mount speakers will typically have a mounting depth of 2" or less, while shallow mount subwoofers will typically have a mounting depth of 3" or less.

No
Tweeter Design
Designs such as cone, dome, semi-dome, balanced dome, and whizzer are most popular. Cone tweeters are simple, efficient and typically are the most reasonably priced. Dome tweeters are used in most home speakers, and provide a smoother and more accurate sound. Semi-dome design is one with a dome placed inside a cone. A Balanced dome driver is a semi-dome with equal reproduction area given the cone and dome portions of the driver. A whizzer tweeter is a separate tweeter cone driven by the voice coil of the woofer.
Dome
Tweeter Composition
Materials such as polypropylene, silk, cloth, and paper are the most common, where as many more recent tweeters are now manufactured with composites such as Aluminum, Titanium, Mylar, and other materials.

PEI is an acronym for "Polyetherimide" which is an amorphous, amber transparent, high-performance thermoplastic.

Silk-Polymer Composite
Woofer Composition
Lightweight woofer cone materials are essential for efficient operation. Poly cones produce exceptional sound and are sturdy against various changes in temperature. Paper cones are very efficient, and when treated for moisture resistance, will perform at a high level. Poly refers to polypropylene, which is thermoplastic or fibers that are polymers of propylene. IMPP refers to injection molded polypropylene, a commonly used process and material in speakers.
Woven Glass Fiber
Woofer Surround
A speakers surround is part of the suspension system. The surround protects the cone and prevents it from being displaced as it flexes out from the basket. It is usually made of a durable material like treated foam or rubber in order to withstand the strenuous job of producing bass frequencies.
Butyl Rubber
Peak Power Handling
Peak power handling refers to the amount of power a speaker can handle during a brief musical burst. The RMS power range figure is a much more reliable rating for determining the speaker's power requirements. The Peak power handling specification is typically rated per speaker unless otherwise noted.
200 watts
RMS Power Handling
The RMS power is the amount of power the speaker requires to operate safely and properly. RMS Power Handling refers to the amount of power a speaker can handle on a continuous basis. We recommend powering your speakers or subwoofer with 80%-120% of its recommended RMS rating. The RMS power handling specification is typically rated per speaker unless otherwise noted.
90 watts
Sensitivity
An efficiency or sensitivity rating tells you how effectively a speaker converts power into sound. The higher the number, the more efficient the speaker and the louder it will play with the same input power. An efficient speaker helps you maximize your available power. Most sensitivity ratings measure the speaker's output with 1 watt of input, 1 meter from the speaker. Some speakers' sensitivity is measured with 2.83 volts of input, instead of 1 watt.
 
Efficiency (1w/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other speakers or subwoofers to determine which one is "louder".
92 dB
Frequency Response
The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
50 - 25000 Hz
Impedance (Per Voice Coil)
The load value (in ohms) that the speakers present to the amplifier per voice coil - the amount of resistance to the current flow. This is a key specification as subs wired in parallel or low impedances can create problems with your amplifier and potentially void all warranties. We encourage you to ask our support department prior to purchase if you do not understand which impedance level will suit your application best.
2.7
Top-Mount Depth
The depth when installed on top of the mounting surface. Measured from the bottom of the speaker's magnet to the bottom of the mounting holes on the rim of the speaker.
2-1/2"
Cutout Dimensions
Refers to the dimensions of the hole, measured in inches or millimeters, required to contain the speaker.
4-11/16 x 4-11/16 
Speaker Grilles
A grating or screen of metal or plastic bars or wires, mounted in front of a speaker as protection. If yes, the speakers will include matching speaker grilles. If no, there are no grilles included.
Yes

Rear Speaker Specifications

Speaker Size (Rear)

Refers to the size of the speaker.

Every vehicle has standard application sizes. Please contact us for your vehicle's specific speaker sizes if you do not know them.

6" x 9"
Design
The number of individual drivers in a car speaker. Speakers with 2 drivers are known as 2-way, 3 drivers = 3-way and so forth. Component systems are often referred to as "separates" because the tweeter is not attached to the midwoofer (main speaker driver) and mounts separately in a location such as a door post. Component systems typically come with an external crossover so you can easily adjust the high and low frequencies sent to both the midwoofer (main driver) and the tweeter. Center channel speakers are great for those looking to capture true surround sound in their car.
3-way
Shallow Mount Installation
This means that the speaker is designed to be installed in areas that do not have a lot of space. Shallow mount speakers will typically have a mounting depth of less than 2".
No
Tweeter Design
Designs such as cone, dome, semi-dome, balanced dome, and whizzer are most popular. Read below for a description of each and other designs.

Cone tweeters are simple, efficient and typically are the most reasonably priced.

Dome tweeters are used in most home speakers, and provide a smoother and more accurate sound.

Semi-dome design is one with a dome placed inside a cone.

A Balanced dome driver is a semi-dome with equal reproduction area given the cone and dome portions of the driver.

An "EMIT" tweeter was introduced by industry leader Infinity. "EMIT" is the acronym for Electro Magnetic Induction Tweeter. They are a thin piece of plastic material with an etched voice coil on the surface of them suspended between 2 very powerful Samarium Cobalt magnets. This design is the key to the EMIT tweeters super fast, crystal clear high end sound.

A whizzer tweeter is a separate tweeter cone driven by the voice coil of the woofer.

Dome
Tweeter Composition
Materials such as polypropylene, silk, cloth, and paper are the most common, where as many more recent tweeters are now manufactured with composites such as aluminum, titanium, Mylar, and other materials.

PEI is an acronym for "Polyetherimide" which is an amorphous, amber transparent, high-performance thermoplastic.

PEN is an acronym for the space age material "biaxially oriented polypropylene naphthalate film".

Silk
Woofer Composition
The woofer cone material is essential for efficient operation. Poly cones produce exceptional sound and are sturdy against various changes in temperature. Paper cones are very efficient, and when treated for moisture resistance, will perform at a high level. Poly refers to polypropylene: thermoplastic plastics or fibers that are polymers of propylene. IMPP refers to injection molded polypropylene, a commonly used process and material in speaker manufacture.
Woven Glass Fiber
Woofer Surround
The flexible ring around the edge of the woofer cone. Surrounds are usually made of cloth, foam or rubber. Rubber and composites tend to last longer and hold up better in harsh environments.
Butyl Rubber
Peak Power Handling
Peak power handling refers to the amount of power a speaker can handle during a brief musical burst. The RMS power range figure is a much more reliable rating for determining the speaker's power requirements. The Peak power handling specification is typically rated per speaker unless otherwise noted.
300 watts
RMS Power Handling
The RMS power is the amount of power the speaker requires to operate safely and properly. RMS Power Handling refers to the amount of power a speaker can handle on a continuous basis. We recommend powering your speakers or subwoofer with 80%-120% of its recommended RMS rating. The RMS power handling specification is typically rated per speaker unless otherwise noted.
125 watts
Sensitivity
An efficiency or sensitivity rating tells you how effectively a speaker converts power into sound. The higher the number, the more efficient the speaker and the louder it will play with the same input power. An efficient speaker helps you maximize your available power. Most sensitivity ratings measure the speaker's output with 1 watt of input, 1 meter from the speaker. Some speakers' sensitivity is measured with 2.83 volts of input, instead of 1 watt.

Efficiency (1W/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other subwoofers to determine which one is "louder".
94 dB
Frequency Response
The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
30 - 25000 Hz
Impedance (per voice coil)
The load value (in ohms) that the speakers present to the amplifier per voice coil - the amount of resistance to the current flow. This is a key specification as subs wired in parallel or low impedances can create problems with your amplifier and potentially void all warranties. We encourage you to ask our support department prior to purchase if you do not understand which impedance level will suit you/your amp best.
2.7
Top Mount Depth
The depth when installed on top of the mounting surface. Measured from the bottom of speaker(magnet) to the bottom of mounting holes on rim of speaker.(Most common application)
3-3/16"
Cutout Dimensions
Refers to the dimensions of the hole, measured in inches or millimeters, required to contain the speaker.
5-1/2 x 8-3/8 
Speaker Grilles
If yes, then package of speakers includes matching speaker grilles. If no, then there are no grilles or included. If optional, then we most likely will also have an optional set of grilles that can be purchased separately.
Yes

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Sonic Electronix

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Product Summary

Manufacturer

Model Number

MM521_MM691

UPC

818060014741

Weight

12.00lbs

Internal SKU

mm521_mm691

Internal Product ID

105411

Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Polk Audio Mobile Monitor 5.25" + 6"x9" Speakers Combo