5.25" 2-way Mobile Monitor Series Coaxial Speakers (Marine Certified)
• 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
• 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
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Will fit most 6x9" and 5x7"/6x8" locations, with appropriate speaker adapter. Click ↑ "Related Items" Tab. |
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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.
Priced Per Pair
Important Note: Polk Audio specifies the nominal impedance of these speakers to be 2.7 ohm. The product box states the impedance to be 4 ohm and the speaker magnet shows 2 ohm, 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 ohm.
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(newest, current model)
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(previous model, replaced by Polk Audio MM522 (MM 522))
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Manufacturer:
Model Number:
MM521
Weight:
4.00lbs
Internal SKU:
mm521
Internal Product ID:
17948
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Great sounding speaker
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
75 found this helpful
Polk MM521
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!
72 found this helpful
Polk Audio MM521 Speakers
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.
71 found this helpful
MM521 = Great speakers.
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.
74 found this helpful
Great Speakers!
I have to say I received great customer service. I ordered speakers for my 09 HD Street glide. They installed perfectly and sound great, so much better than the stock speakers. I would recommend these speakers to anyone.
68 found this helpful
Great sound and lightweight!
I purchased two pairs of these speakers and the sound is phenomenal. I bought them for a 2 seat roadster with a very loud cabin and they have done very well on only head unit power. As a plus, they're very lightweight but sturdy. I'd highly recommend them.
68 found this helpful
Polk is it
Awesome speakers for my topless Jeep, got rained on several times and NO problem.
66 found this helpful
Polk Audio MM521
Works Great, I have had these installed for more than 6 months. Even though they have the correct size for a Plymouth Voyager, they are a little too tall. I got them mounted, but not recommended for this minivan...they sound spectacular though!
66 found this helpful
pretty damm goof
Very tight sound, awsome looking speaker as well. Good bass level from such a small speaker.
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Modern vehicles often require specific brackets, wiring harnesses, and mounting solutions. A fit guide ensures:
Whether you're replacing a factory stereo or upgrading your entire audio system, the Fit Finder eliminates uncertainty.
