6 1/2-inch coaxial loudspeaker
6 1/2" coaxial
Designed to Perform
The MM651 is a 6 1/2-inch coax speaker designed to fit in a variety of applications. As a result of 3 years of Polk research and development, the new MM series have been designed to offer unparalleled sound quality with exceptional fit to meet virtually any application. Borrowing technology from our flagship SR Series, the MM Series offers exceptional value for the price. Through the use of high-tech composite baskets, powerful neodymium motor structures using oversized voice coils, and state-of-the-art woven glass composite cones, we offer high-end audio performance normally found only in the most expensive loudspeaker systems.
Space age materials reduce weight of components while offering rock solid reliability, advanced looks and ultra high performance.
Neodymium magnets a rare earth metal offering exceptional strength to performance ratio, found only in the most exotic speakers, saves tremendous weight. Don’t let the sound system weigh your vehicle down. Since the magnet is smaller, the speaker can fit into more applications.
Carbon composite basket based on the spokes of a wheel is lightweight, will not flex during peaks and looks great! Don’t be afraid to show off the back of your speaker.
Woven glass composite cones feature tremendous stiffness-to mass ratio. Lower mass means faster transients and finer detail.
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.
Marine Certified Polk MM Series speakers are built tough to withstand the toughest environments so they are perfect for use in boats of all types. That’s why Correct Craft offers Polk speakers in their award-winning Nautiques ski and wakeboarding boats.
Large-diameter voice coils (30mm) in drivers increase reliability and power handling capacity.
Swivel mount tweeters allow precise aiming of sound.
Stylish grille is included.
All Polk products are made using the best materials and the most advanced manufacturing techniques. They pass the industry’s most exhaustive quality tests, including drop testing, extreme signal response and UV & salt exposure testing. Polk loudspeakers are built to perform for a lifetime.
|Type||Silk composite dome|
|Mid / Woofer|
|Diameter||6 1/2" (16.51cm)|
|Type||Dynamic Balance driver with poly-composite cone|
|Total Frequency Response||40-25kHz|
|Nominal Impedance||2.7 ohms|
|Driver Diameter||32" (81.28cm)|
|Magnet Weight||5.3 pounds|
|Recommended Amplifier Power||15-125 watts per channel|
|Cut-Out Diameter||5 1/16" (12.86cm)|
|Full-Range Mounting Depth|
|Top Mount||2 5/8" (6.67cm)|
|Bottom Mount||2 7/8" (7.30cm)|
|Unit of Measure||pair|
|Speaker Warranty||1 year parts and labor (original purchaser)|
Specifications, dimensions and features subject to change without notice. For more information call us at 1-800-377-7655 (USA and Canada). Outside of North America call +1 (410) 358-3600.
11 reviews with an average of 5Write your own review
by Dave G, June 11, 2009106 out of 177 people found this review helpful.
Sound quality. Lightweight. Waterproof (or Marine Grade).
Instructions could be better or less generic - especially about positioning the tweeters as I've read that complaint in several reviews.
I installed these speakers in the fairing of my 2008 HD Ultra Classic motorcycle because I was looking for a larger (6.5") waterproof speaker with decent specs and a rating closer to 2Ω rather than 4Ω. The sound quality is excellent matched with the stock Harmon-Kardon head unit. Excellent mids and highs and enough volume without distortion to drown out my loud exhaust and wind noise at highway speeds. For coaxials, you can't beat the quality. Note to folks who can't reposition the tweeter: Don't try to move the housing - it's in a fixed position. The tweeter pivots WITHIN the housing, so just push gently on the tweeter grill near the edges to reposition the tweeter.
by Byron, October 26, 200898 out of 186 people found this review helpful.
Great sound, much better than stock automotive speakers. Reasonable price for quality
Only gave the speakers 4 stars because while I was examining the speakers prior to installing one slipped from my grasp and dropped about 1" to the table and put a nasty dent in the tweeter grille. Just thought the tweeter grille should be a little more sturdy. Otherwise, 5 stars!
I purchased these to install in my Honda S2000 as rear speakers, mounted just behind the headrest. The improvement in sound over the stock Honda speakers located in the door was just unbelievable. I can now hear my music without having to turn the volume up to distortion levels. I give these speakers a 5 star rating for sound quality.
by VHP, August 6, 200893 out of 169 people found this review helpful.
Great clarity and definiton of sound. I do not play a radio loud and these speakers sound wonderful at low to medium volume. BUY THEM
These were installed in the front and rear doors of a 2007 Inifinty M35 with the base radio. I have been complaining to the auto dealer that there was no depth or clarity to the sound. The dealer rep said no one changes out the Infinity system because they are so good. I talked to installation shops and some said don't change the speakers because they are of such good quality add a amp, others said change the speakers. Confused I called Polk help and was advised to try the speakers first. These MM651 speakers make my system awesome. My sound is now better with the basic stock Infiniti radio than the ultra premium Bose that I have in my Audi A6. I am totally satisified and really appreciate the help from the Polk reps.
by Peter Hobbs, January 2, 200993 out of 165 people found this review helpful.
Clarity of High's, and fullness of Mid's.
A little pricey, but you do get what you pay for.
I knew that polk made really good quality stuff since I have M-series speakers in my home theatre. My 2001 toyota corolla had four factory 6 1/2's the whole way around. I upgraded to 4 of these polk's and the mid's and high's sound really good. I thought having the tweeter in the speaker might make the highs sound muddy, but I was impressed with how clear it was. I am very pleased with these 651's.
by Joel Trembath, October 21, 200892 out of 167 people found this review helpful.
bass and treble greatly tuned to be "there"
Possibly not enough mid to link bass and treble. Just barely though
Great speaker money wise, awesome lows and highs. Directional tweeter means that there is a way to control "brightness" of tweeter if too harsh and crossover a great asset for clarity. Bass is very defined and definitly there but possibly not enough between bass and treble to make them outstanding
by clay, November 11, 200885 out of 150 people found this review helpful.
pure sound quality, smooth highs, solid mid-bass,handle large amounts of power without distorting, fit in just about any aplication you can imagine!
tweeters are supposed to be movable? put a dent in one of them trying to point the tweeter upwards. the other tweeter moved easily. im nitpicking now.
first 6 1/2" speakers i've ever seen that could be fit in the factory kick pannel locations of a 1992 corvette! installed by way of removing the factory Bose speaker pod, cutting a hole in the factory grill (which is carpetted plastic) and mounting them that way. black grills look great against the black carpet. i was going to use these in the rear and install 4" upfront like most people do but after looking at the size of these i had to try it. the front stage is the best i've ever heard in a vette! it sounds like the sound is coming out of the defroster vents. the angle of the kicks, focusable tweeters and 90 watts per channel from a Polk PA500.4 make this possible. im using the rear channels bridged for a single 10" woofer. i cant wait to get the Mobile Monitor 10" woofer to replace the oldschool one im using now. if you're wanting truely high end speakers but on a mid-range budget but these! end of story.
by Eric, May 31, 201069 out of 105 people found this review helpful.
Great sound quality, huge increase in volume, super compact. I would have paid twice the asking price.
Would have loved to get a few sets with white covers. Covers too open and do not protect speakers from impact damage. Have to have room in bulkheads for crossover.
I just installed a set in the tower my Chaparral yacht. The tower is very thin and I was worried that I was never going to find a speaker with any range to fit. This set was by far the most compact and had the best sound at the store. I have never heard a better sounding co-ax speaker. The boat has a sixteen channel Dennon stereo system and I'm going back to the store to get enough of them to replace every speaker on the boat. My bridge has never sounded so good. The aimable tweeters give me perfect stereo and my system is so much louder, it blows away the wind noise.
by Sandro, August 17, 201146 out of 64 people found this review helpful.
Loud and Clear ! no distortion at 100 watts
No weakness noticed yet at all
Wow! Holy cow Batman ! these things Rock! Very clear and very good bass. Drums sound nice and defined. I think my neighbors like AC/DC. They must like it, because they keep coming out into their drive way to stare across the street at my garage at 10:30 pm while I'm testing out my new stuff. Buy these speakers they are worth every penny.
by Walt S, January 27, 201135 out of 50 people found this review helpful.
The overall build quality is excellent. Amazing sound quality, power handling and durable.
I love these speakers. These are some of the best sounding speakers in any price range. If you love clean, crisp and very detailed sounding speakers these are the ticket. I have some of these installed in our company demo boat in saltwater with plenty of clean amplifier power. They get so loud and play so clean that you will think that you hair is about to stand up. Aqua Acoustics, Jacksonville, FL
by Blake, April 18, 201214 out of 25 people found this review helpful.
colorless, volume, clarity, transparency, 2 ohm impedance
I am running these in a 2007 Honda Accord Coupe along with the MM691's, a Dayton Audio Reference HO 15", an Eclipse 5504 headunit, and an Eclipse XA5000 amplifier that is doing 75x4 (thanks to the 2 ohm impedance of these speakers) and 300x1 for the sub. I have had Pioneer REV Series and Focal Polykevlar before, and these are so much clearer and louder it's silly. These sound as good as my 3 way Dayton Reference speakers that I built for my house. They are completely colorless, absolutely detailed, and can get louder than I can stand. The last speakers I will ever buy.
by Mr. X, July 24, 20121 out of 1 people found this review helpful.
Waterproof, power handling, sound quality
Put a pair of these in my boat powered only by the deck. I cant even hear the clarions that were put in there! Crank them while full throttle and still hear with great quality!
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