Polk Audio DB521 5.25-Inch Coaxial Speakers (Pair, Silver)

I have been a long time fan of Polk audio and use their speakers for my home theater setup. These arrived quickly, as is generally the case with Amazon, and the product was packaged quite nicely. I had no issues with the shipment.The vehicle I installed these speakers on is a 2004 Wrangler and they were installed in front speaker boxes with the 4x6 to 5.25 adapters that are sold on Amazon ($14). They were fairly easy to install, especially after taking a few minutes to plan how I wanted to mount them. They have normal terminals for which quick disconnects can be used. I ended up buying some cheap ones from Auto Zone for like 3$ for a pack of 20.The set comes with 2 mounting spacers (needed if you have a speaker location with a smaller diameter speaker slot for example like my Wrangler), a rubber gasket to create a good seal, two speakers, 8 long screws and 8 short screws, and the grill. The only unfortunate downside to this set is that the smaller screws will not work if you need the mounting spacers. They are approximately 1/6th of an inch long and are used to secure the speakers in a normal speaker slot. Meaning they are too short to be used with the grill or with use in a spacer. Luckily I had some drywall screws that were almost identical to the 8 larger screws and I was able to mount them with no issues. I have uploaded some pictures of how they fit and of the smaller screws. I am sure they would probably work to an extent but would not want to take the risk that they would fail with only so little plastic holding them in.Great product and reasonably priced. In fact they are so reasonably priced that they are about 30$ cheaper than Crutchfield or any other comparable competitor. They offer a great range of sound and have completely changed how the audio in my vehicle sounds. The sound from the front speakers is still a little off, but I believe that I need to go with a power block for my H/U as they should sound much clearer once they have some more power going to them. The Jeep is also pretty horrible when it comes to acoustics. Overall I am completely satisfied with my Polk products and would definitely purchase the 521s and 621s again in the future.

They sound great!

Improved sound quality over factory speakers in 2000 Jeep TJ.

I bought these speakers to replace some crappy stock speakers on my 2011 Kawasaki vaquero 1700. They fit in the existing speaker holes just perfect and we're slim enough to not interfere with the speak grills. Mounted up perfect and look great. I also installed a small Alpine power pack amplifier to help drive these speakers and they sound leaps and bounds better then the stock kawi speakers. They make a noticibly huge difference. When the bike is parked they flat out rock and sound way clearer and louder then before. However when I get going down the freeway at normal cruising speed (60-70 mph) they do loose a lot of sound. Don't get me wrong they still sound good but I don't know if there is any 5 1/2 speaker out there that will do what all of us would like them to do at those speeds. By design they are just not big enough to compete with the wind and road noise. Like I said before they sound clear but can't handle much bass at all. Again by design they shouldn't. Overall they are nice and better then stock and we'll worth the price. Just don't expect them to handle R&B or Rap music at high volumes. Rock and that type of music they do much better with. Hope this helped someone out there. ;)

I've had these installed in the front doors of my Olds Intrigue for the last 5 years and they still put a smile on face. Mids and highs sound so clean and realistic. It's about as good as you could ask for from a 5.25 door-mounted speaker.My car used to have factory sail panel tweeters, but I was on a budget and decided to go with coaxial speakers. I don't regret it. Since I can aim the Polk tweeters, I can barely tell the highs aren't coming from the sail panels anymore.They also blend very well with the two 8" subs in my rear deck. I was concerned that a 5.25 speaker wouldn't be able to play very low... During setup however, they played an 80Hz test tone with so much authority I was sure it was coming from my subs which were muted!I should mention these things want POWER, don't let the 45W RMS rating fool you. I'm powering them with a 100W RMS amp with the gain properly set and these really come to life. You can't power them with your head unit and expect them to sound amazing. Unless you've got a really nice head unit, you're probably going to end up with underwhelming sound (harsh mids/highs, little low end).I'm very pleased with the speakers and how my whole system sounds. I've become a Polk fan because of these. I feel like they put more focus on engineering a good sounding speaker rather than marketing and silly gimmicks (you won't find a Polk with a 40-way tweeter, Super Mega Woofer™ and skull shaped grill).