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Polk Audio MM651

6-3/4" 2-way speakers

27 Reviews | 1 question - 1 answer

Item #: 107MM651

In Stock

Was: $249.99

Price Break: -$130.00

Installation gear for most cars

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Overview

Our take on the Polk Audio MM651

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 MM651 6-3/4" speakers feature honeycomb-textured woven glass fiber composite woofer 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.

1" silk dome tweeters add a sweet high end that blends perfectly with the low notes so your music stays in harmonic balance, from the electric bass all the way on up to the cymbals. Swivel mounts on the tweeters allow you to aim the high notes to produce a superior sound stage in your car.

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 all factory and aftermarket stereos.

Note: Polk describes this model as a 6-1/2" speaker. Most manufacturers designate this same frame size as a 6-3/4" speaker. For simplicity's sake we list it as a 6-3/4" speaker.

Priced per pair

I installed these along with a pair of MM691 and a ppi 900.4 amp in my boat. These speakers have it all. Good looks, great sound and get really loud. These are some of the best sounding marine speakers I have heard and in this price range they are the best.

Dave 220lx, Olive Branch, MS

What's in the Box:

  • Two 2-way 6.75" speakers
  • 2 Grilles
  • 2 Passive crossovers
  • 2 Mounting ring adapters (includes GM/Chrysler 6-3/4G)
  • 8 Hex-head screws
  • 4 Phillips-head screws
  • 8 Speed clips
  • Owner's Manual
  • Product Registration information sheet

Product Highlights:

  • 6-3/4" 2-way speakers (pair)
  • woven honeycomb glass fiber composite woofer cone with butyl rubber surround
  • 1" silk composite dome tweeter with swivel mount
  • certified for marine use
  • 2.7-ohm impedance for extra power (compatible with all factory or aftermarket car stereos)
  • power range: 15-100 watts RMS (200 watts peak power)
  • frequency response: 40-25,000 Hz
  • sensitivity: 94 dB @ 1 watt
  • top-mount depth: 2-5/8"
  • warranty: 1 year
  • Our 60-day money-back guarantee
Reviews

Polk Audio MM651 Reviews

Average Customer Review:

27 Reviews

amazing

Written by: Dave 220lx from Olive Branch, MS on May 20, 2016

Crutchfield Customer Review (What's this?)

I installed these along with a pair of MM691 and a ppi 900.4 amp in my boat. These speakers have it all. Good looks, great sound and get really loud. These are some of the best sounding marine speakers I have heard and in this price range they are the best.

Pros: Good looks Great sound Bang for the buck

Cons:

2016 Harley Road Glide

Written by: Vincent from Whitehall, MI on May 19, 2016

Crutchfield Customer Review (What's this?)

Very crisp and clean sound so much better than stock

Pros: Great sound

Cons: mount base is thicker than my stock so my screws were not long enough and the screws provided were long enough just not big enough round.

Polk speakers

Written by: Michael M from Winchester, TN on May 18, 2016

2008 Ford F-150
Crutchfield Customer Review (What's this?)

Love Polk Audio products. I installed these speakers on my boat. They sound great.

Pros: Crossover included.

Cons: A little pricey but well worth the cost.

Good quality.

Written by: Spens W from Laurel, MD on May 17, 2016

2015 Chevrolet Malibu
Crutchfield Customer Review (What's this?)

For a factory upgrade these speakers are great. Easy to install but it gets a little tricky on where to mount the crossover. The quality of the highs and mids is pretty outstanding. You get great clarity at high volume level. I did wish that the bass shined through a little more especially for the price.

Pros: Great sounding highs and mids.

Cons: Need more bass.

polk mm651

Written by: js from Algonquin, IL on May 10, 2016

Crutchfield Customer Review (What's this?)

I got these for my boat because of the reviews. These things are great!

Pros: sound great, easy to install, great quality

Cons: none

Awesome

Written by: Rex W. from Longview, Wa. on April 27, 2016

2007 GMC Sierra 1500 Classic

Easy install, great highs and mids. Needs a sub for bass.

Pros: Awesome mids and highs

Cons: None

Polk mm651 and mm691 in dodge Ram

Written by: x from Florida on May 10, 2015

These speakers sound awesome, when they work. 2 years after installing them in the stock door locations of my 2500 Dodge Ram one of the front mm691's low frequency driver just stopped working. The high frequency side is fine. The LC circuit is fine and I have never overloaded them. Also, upon removing the speaker for root cause analysis I see that the rubber surround has one small crack. In addition to this speaker having an issue, one of the rear mm651 also fried. Again the LC circuit is fine and in this case the speaker still plays, but with awful low frequency response. I spent a lot of money on these speakers and then a lot of time making them fit in the Ram. Polk brand speakers of the past were proven reliable for me, but these MM units are very disappointing.

Pros: good sound initially

Cons: Early failure. Poor durability and poor ageing. Very expensive

MM651 - 2010 FLTRX Road Glide

Written by: MattE from Rhode Island on December 14, 2012

Not much to say other than BUY THESE SPEAKERS. The efficiency of the drivers is outstanding, people who are not familiar with audio equipment always overlook this rating. 94dB@1Watt is extraordinary, especially when used in a motorcycle environment as in my case, they are also 3 Ohm impedance, which will draw more power from your source/amplifier (if it doesn't melt it first). The MM651 also has arguably the highest RMS/Peak power handling (when comparing realistic claims). Butyl Rubber surround, 1" tweeter and flexible installation options round out the great features of Polk's moderately priced superstar. Just do a Crutchfield comparison between the Polk MM651, the Focal K2 Power 165KRC, the JL Audio C5-650X, the Focal Performace PC 165, the Alpine SPR-60, and the Focal Integration IC 165. This comparison included speakers labelled as 6-3/4" with a (listed) price range of $199.99 all the way to $679.99. I know some people have more dollars than sense and will always buy the most expensive item available; regardless of what it is, however, I personally find it hard to stomach an extra four hundred thirty-dollars. As always Crutchfield is the go-to-source for all of the best equipment for your home and auto.

Pros: Performance > Price, 94db Sensitivity, Butyl Rubber Surround, 1" Dome Tweeter, 3-Ohm Impedance, Frequency Response, Power Handling... May I stop now?

Cons: I can only fit two on my Harley.

Polk Audio MM651

Written by: JordanZ from SLC, UT on August 3, 2012

Crutchfield Customer Review (What's this?)

These speakers do install into both the front and rear doors on a 2012 Subaru Impreza with the same caveat that Crutchfield mentions for the front doors, you have to drill new mounting screw holes. The rear doors have plenty of clearance and I just used some foam weather stripping around the speaker hole to seal up any gaps in both set of doors, it's a couple dollars at most hardware store. Other than that they couldn't sound better for being pushed with the stock receiver, can't wait till someone makes a dash mount for this car and I can throw in my receiver, amps, and subs from my old car. I know these things will sound even better with a decent amp pushing them. I grabbed these to replace the 5x7" Polk MOMO's I had in my old car that don't fit here.

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Polk Audio MM651

Written by: Anonymous from jersey city, nj on June 10, 2012

2001 Hyundai Accent
Crutchfield Customer Review (What's this?)

these speakers trully deliver a punch for such small package

Pros: excellent bass

Cons:

Polk Audio MM651

Written by: Rob M from Jersey Shore on June 5, 2012

2006 BMW 5 Series
Crutchfield Customer Review (What's this?)

these speakers are amazing...they sound soo good in my silverado, perfect fit. I live the external x-over..clean sound...

Pros: ez install , handle lots of power

Cons: none

Polk Audio MM651

Written by: Anonymous from Tucson AZ on May 20, 2012

2012 Jeep Wrangler Unlimited
Crutchfield Customer Review (What's this?)

These are amazing speakers. Such an improvement over the stockers. Nothing I can complain about. Crutchfield even had the lowest prices as well has having them in stock.

Pros: Ease of install Great sounding

Cons: Had to pay for them

Excellent Speakers

Written by: BrentB from Denton, TX on May 10, 2012

Crutchfield Customer Review (What's this?)

Great sound quality and build. Using them in my tower speakers on my boat.

Pros: 2 ohms, crossovers included

Cons: none

Polk Audio MM651

Written by: Anonymous from Philadelpha on April 2, 2012

2010 GMC Sierra
Crutchfield Customer Review (What's this?)

Love these speakers. I was a little worried about the crossovers that were included, but I got some connectors from Radio Shack, and it worked great. And the directions from Crutchfield were excellent!

Pros: Great sound. Easy for DIY with the directions.

Cons: None

Great

Written by: Kelly from Texas on March 16, 2012

2007 Chevrolet Silverado 1500 Classic
Crutchfield Customer Review (What's this?)

Replaced Polk DB speakers in front door 2007 chevy pickup. Major improvement! Have the DB 4x6 plate speakers in rear. Hooked both up to 900w amp and WOW, cant believe how clear and loud. Cant lose with this speaker!

Pros: ROCK ROCK ROCK

Cons: None

Amazed

Written by: Mcaletzr from ochester,ny on March 12, 2012

2008 Honda Civic LX
Crutchfield Customer Review (What's this?)

I'm amazed that after ordering he mm651 Polk speakers and then receiving them, the amazement kick in when extra parts was included It made my day. Job was simple because of Crutchfield.

Pros: Parts are included

Cons: None

Awesome

Written by: Chris from AZ on March 10, 2012

2006 Nissan Xterra
Crutchfield Customer Review (What's this?)

Huge improvement in sound quality over factory speakers!! I was hesitant about buying these at first because Crutchfield says they do not fit in my rear doors, but a simple template ring took care of that. No complaints at all.

Pros: Solid bass response for a 6.5in coaxial, impressive warmth.

Cons:

Scott

Written by: ScottP from Moore, OK on March 3, 2012

Freakin love these speakers. I catch myself turning the radio down to find out what the unfamilar sound is, just to realize it's part of the song I'm listening to but never heard the "clarity" that you should hear. Nice base for a 6 3/4" speakers. Dropped right in on my 02 Sierra front door panels. Plan on getting some 6X9s to put under the back seat in some small enclosures... will definately go with the MM691s. In a word... Awsome.

Pros: Well made, compact magnet, Sound wicked sick Includes crossovers

Cons: NONE

AWESOME

Written by: anonymous from Columbia, MO on February 8, 2012

2012 Subaru Impreza
Crutchfield Customer Review (What's this?)

Using these as front speakers in an Impreza, with db651's in the rear doors. God, I wish these fit all 4 doors easily. I am using the stock head unit with no aftermarket amp or sub. These sound great. Very full sound, even at the bottom end. I listen to rock (the who, zeppelin, kyuss, local h, blue oyster cult) and these handle that type of music well. If you're into rap, get a sub. If you're cheap and still wanna rock, these are great.

Pros: full sound only need sub in very demanding applications

Cons: external crossover meant installation took 3 extra minutes of my precious time weren't free.

Polk mm651

Written by: Jaycue from Deer Park, NY. on February 4, 2012

Crutchfield Customer Review (What's this?)

These speakers sounds excellent. They put out really nice highs and midbass, the soundstage is really good. Had to modify the rear deck of my 2010 civic coupe. Sound really good at low levels.

Pros: Sound stage and quality.

Cons:

Nice speakers

Written by: Tim from South WIndsor, Ct on September 16, 2011

2011 Jeep Wrangler Unlimited
Crutchfield Customer Review (What's this?)

These are great all around full range speakers. I bought these to compliment the mm components I had already installed. Crutchfield says they don't fit in a 2011 jeep wrangler but they do! In fact they fit excellent. The overall sound is good off just the deck. I have the front components amped and they sound great, so these are used to provide rear-fill. And as always, Crutchfield is superior in all ways that I have ever dealt with them. They truly are a rare company with the perfect mix of qaulity gear.

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Great sound....fitment issues.

Written by: Old Subaru WRX from Earth on June 23, 2011

Cons: These speakers have a very wide basket (but are not overly deep, which is a plus). They didn't fit in the rear openings without taking an ANGLE GRINDER to my car! That said, the old WRX has terrible speaker fitment issues anyway, with any brand. Crutchfield warned me about this, but I did it anyway, so it's my fault. Also, there's a bit more work with mounting the crossovers and running dual wires, but not much. Pros: The sound. Once in, they sound amazing. Like other reviewers, there seemed to be a few-day "break-in" period with these speakers. After about a week, you can really hear all the details better, and they hit very hard for a door speaker running off a JVX XR610 (excellent, BTW) head unit. At 2.7 ohms, they will go uncomfortably loud with no distortion, and after 6 months, everything works great. Highly recommended. They sound amazing. Fitment issues were really the problem with my car and I.

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Perfect complement

Written by: KENCP6 from Bakersfield, CA on August 11, 2010

Crutchfield Customer Review (What's this?)

After installing infinity reference in my rear doors and the polk mm componets in the front i quickly realized i needed an upgrade in the rear as the infinitys were not getting the job done up against the polks, "doc" at crutchfield recomended these and what a difference they are the "match" to the polk components and made all the difference, i could tell there was something missing with the infinitys but not now, putting these in the rear doors with some dynamat all around totally kicked my system up a big notch, i would recomend these to anyone looking to upgrade weather or not you have power behind it.

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amazing bass

Written by: curtis from alaska on October 28, 2009

Crutchfield Customer Review (What's this?)

I have 2 sets of these in each of my vehicles. I cannot believe the amount of bass these put out. When they are broken in they sound amazing. Dont settle for a cheaper speaker , these rock!

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Polk Audio MM651

Written by: gerald from titusville Fl. on January 18, 2009

I purchased 6.5's and the 6x9's to match. I replaced premium series ($500.00) 6.5's that had blown with 50 w rms and a x-over. I couldnt afford the top of the line polks, and hoped that these would tide me over till I could. AT FIRST... they sounded so horrible I couldnt believe it. I read about people saying they got better over time. They where right. After I sold the amp with built in x-over and installed diff. amp w/o x-over, I realized how much bass they really put out. The quarts couldnt compete at all as far as bass and mid bass. That extra bass pumping through them now broke them in, in a hurry. Now they sound fantastic. I wont lie and say as spacious and natural as the quarts, but the sound stage is high (right over the dash), their frequency extension is good with no harshness (the bane of Boston Pro's), and also very focused with no hole in the middle. MUCH better than I was expecting. They didnt sound good at high volume levels at first but after the break in period, now they get darn loud and sound great. The only draw back is how much my door rattles now, and the cone is kissing my factory grill making it buzz. For the price you cant beat them. Double ,triple or quadruple it and now your out of their class. Two thumbs up for me at this price.

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MM651 SPEAKERS

Written by: ERNIE from NASHVILLE on December 15, 2008

Crutchfield Customer Review (What's this?)

polk mm651,installed in avalanche,all 4 doors, mounted the crossovers in the doors, mounted speakers in stock locations,trimmed the plastic round opening of the door panel so the speaker had additional clearance on excursion.use crutchfield speaker mounting rings on front doors and the polk mounting rings on the back doors,all 4 speakers are top mounted,this way you will have the clearance needed for the windows.speakers sound excellent, punchy on the lows,clear and smooth on the mids and highs.powerd by jvc headunit(20Wx4).no sub.I tryed db651s first,lack of lowend clarity.the mm651 have much better lowend.,with an over all audiophile sound,the cost differance was worth it.crutchfields service is excellant,thank you(Jordan,Jason).the next step would be to add an amplifier.

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Polk Audio Rules

Written by: Richard from Elizabethtown, KY on September 21, 2008

I now have ten Polk Audio speakers crammed into the cab of a GMC cube van(used to be a moving rental van). A pair of component, two pair of eight inch subs(MM2084), and the pair of full range MM651s, all of which are driven by twenty- five hundred watts of amplifiers. I used the MM651s to "fill in a void" located in the center of the cab and BOY HOWDY did they fill it in. Now I fell like I'm "in the speaker" instead of being surrounded by them. Better yet, I can't here myself sing anymore!!!

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Details

Hands-on research

What's in the box?

Download the Polk Audio MM651 manual

  • Two 2-way 6.75" speakers
  • 2 Grilles
  • 2 Passive crossovers
  • 2 Mounting ring adapters (includes GM/Chrysler 6-3/4G)
  • 8 Hex-head screws
  • 4 Phillips-head screws
  • 8 Speed clips
  • Owner's Manual
  • Product Registration information sheet

Product Research

Features

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.

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.

Silk/Polymer Composite Swivel Tweeters: The 1" liquid-cooled, silk/polymer composite tweeters provide clear, detailed highs. The 15-degree swivel tweeter housings deliver direct, detailed imaging; instantly adjustable through the grille.

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.

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

Crossover: The speaker comes supplied with two separate 2-way crossovers; one for each speaker. Each crossover input 36" lead is terminated with tinned wire, and the two 20" output leads (one for the woofer and one for the tweeter) are terminated with female quick-slides. The positive woofer lead has a 0.250" female quick-slide and the negative woofer lead has a 0.187" female quick-slide. The positive tweeter lead has a 0.187" female quick-slide and the negative tweeter lead has a 0.110" female quick-slide. These quick-slides connect directly to the woofer and tweeter terminals on each speaker. The separate 2-way crossover network sends the appropriate frequencies to each driver for cleaner sound and better imaging. Dimensions: width = 3.515", height = 1.015", depth = 2.645"

Mounting: The speaker itself has 4 mounting holes for a standard 6-3/4" application. The supplied mounting ring has multiple mounting holes for non-standard 6-3/4" applications, allowing the speaker to fit more vehicles.

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

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.

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.

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Q & A

Customer Q&A

1 question already asked

Thanks for your question. The SquareTrade warranty runs concurrent with the manufacturer warranty and beyond the 1 year. You can find more information on the SquareTrade link here: http://www.crutchfield.com/Promo/squareTrade.aspx [ Kenny  Apr 19, 2016 ]  Staff
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