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Polk Audio MM651

200W 6.5" 2-Way Mobile Monitor MM Series Coaxial Speakers w/ Silk Tweeters (Marine Certified)

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General Features

  • 6-1/2" Mobile Monitor MM Series 2-way Marine Certified Speakers
  • Power Handling:
    • Peak: 400 watts per pair / 200 watts each
    • RMS: 200 watts per pair / 100 watts each
  • Woven glass composite cone woofer
  • Butyl rubber surround
  • 1" Silk composite dome tweeter
  • 2.7 ohms impedance
  • Klippel distortion analyzer
  • 1-1/4" Large diameter voice coil
  • Neodynium magnet structure
  • Carbon composite basket
  • Top-mount depth: 2.625" (6.67cm)
  • Cutout Diameter: 5.0625" (12.86cm)
  • Grille Included
  • Authorized Internet Dealer
  • 90 Day Manufacturer's Warranty

Priced Per Pair

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.


Second Depth
The second depth is used only when the box is slanted or angled. This value is the top measurement and it is measured in inches.
The front-to-rear depth of the item, in inches. If the item is angled or slanted, this value is the bottom measurement.
The height of the item, measured from top to bottom, in inches.
The width of the item from left to right (side-to-side) measured in inches.
Color of handle.

Warranty and Return Policy

Parts Warranty Duration
90 days
Labor Warranty Duration
90 days
Warranty Provider

Summary of Customer Ratings & Reviews

Rating Distribution

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Average Attribution Rating

Browse 5 questions and 21 answers
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Why did you choose this?
Sonic Electronix Store
To use with active crossovers in a bi-amp system. I will not be using the passive crossovers provided. I have other Polk speakers and have had good experience.
Donald P on Dec 28, 2016
A professional audio installer that tunes Bose systems in general motors vehicles recommended these or the C3-600s for my G8 GXP. I saw the amazing deal your website had on these MM651 speakers so I decided to go this route to save myself a lot of cash.
Kevin B on Dec 7, 2015
Previous experience with Polk MMC650 which is no longer available. This is the new replacement model. Fantastic sound, deep bass smooth response from 100hz to 20khz.
Paul in on Mar 17, 2016
As far as marine speakers go, Polk Audio is the winner hands down. Push the power with no distortion. Built in crossovers take the guess work and hassle out of everything.
Billy B on Sep 15, 2015
Since this speaker is rated at 2.7 ohms, which is better to run, a 2 ohm per channel amp or a 4 ohm per channel?
Brian K on Feb 5, 2015
Best Answer: When you hook up the speaker, it will automatically run at 2.7 ohms. You can't "set" impedance. So make sure your amp is able to run at 2 ohms per channel because if it is only 4 ohm stable you will likely fry the amp
Reply · Report · Tripp G on Feb 5, 2015
· Add Answer · I Have This Question Too (7)
I am looking at perchasing Polk MM651's and the Polk MM691's. What 4 Channel Amps can you recommend and what Ohm's? Would a 75x4 or 100x4 4 Ohm be a good match?
Steve C on Nov 11, 2015
Polk Audio MM651
Polk Audio MM651
Polk Audio MM691
Polk Audio MM691
Kenwood X450-4
Kenwood X450-4
Best Answer: I pushed my MM651's with 75watts at 4ohms and they sounded good for a replacement speaker.
Reply (1) · Report · John E on Nov 11, 2015
· Add Answer · I Have This Question Too (1)
What are the dimensions of the crossover unit?
A shopper on May 2, 2016
Best Answer: It has been a while since I installed these speakers and I sold the boat that I had them in. From my memory I would say that the are 4" x 3" x 1". That probably isn't exact but they shouldn't be any bigger than that.
Reply · Report · drew i on May 2, 2016
· Add Answer · I Have This Question Too (0)
Adding these GTO 938 to built Harley system using Rockford Fosgate PBR300.2 amp, 2 channel ,2ohm stable and Polk MM651 speakers. Trying to figure out how to wire 2 speakers per channel. 4 speakers total 2 per channel For 2 ohm amp? These speakers have only 2 connections on speaker, and the Polk has a 4 connection with a box then 2 connection to speaker input. Any help would be greatly appreciated. Thanks John
John W on Oct 24, 2015
Polk Audio MM651
Polk Audio MM651
Best Answer: Unfortunately your setup cannot be completed as you wish. Wiring two 2ohm speakers - like the GTO938 - will present a 1ohm load or a 4ohm load, which is fine, but your Polk Audio MM651 offer a completely different load, at 2.7ohms. Wiring the Polk Audio MM651s together will present a load Far different than that of the GTO speakers, this will stress the amplifier.

We suggest a separate 2-Channel amplifier for the second set of speakers.
Reply (1) · Report · Rick MStaff on Oct 28, 2015
· Add Answer · I Have This Question Too (0)

Product Summary


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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 MM651