The Polk DB+ series of speakers is a popular option for cars, but these speakers are also marine certified. In addition to being durable enough to handle salt, water and the sun, the speakers have the sensitivity and the power handling to push your tunes out past the wake. While these speakers don’t provide high-end audio quality, the audio performance is great for the price. In addition, with a slim mounting profile, the speaker fits into nearly any enclosure.
I tested the audio quality by recording the speaker as it produced a sine tone that transitioned from 20Hz to 20kHz, which represents the spectrum of human hearing. After recording this tone on a loop for five minutes, I used a frequency signature filter to create the average frequency signature of the speaker. Then I compared its frequency signature to the original audio file and graded the low, midrange and high frequencies.
The DB+ 652 received its best grade in the high frequency range with an A+. In fact, it was the best speaker I tested at producing high frequencies. Only the Fusion FR6022 and Clarion CMQ1622RL speakers were close. However, while those speakers produced elite grades for the midrange and lows, the DB+ 652 received a B- for the midrange and B for the lows, reflecting a less-balanced audio performance. However, this speaker is also one of the most affordable boat speakers. The performance is high-value when taking the price into the account. In many ways, it’s the more affordable version of the Polk MM1 652 marine speakers, which cost more than twice as much.
The DB652 has a sensitivity rating of 92 dB, which means that the manufacturer claims it is efficient enough to create a volume of 92 dB (measured at 1 meter) with 1 watt of power. This sensitivity rating should make it one of the most efficient marine speakers on the market. Only the Polk MM1 speaker has a higher sensitivity rating. However, in my comparative loudness test, which compared each speaker's efficiency by measuring their volume on the same stereo, both Polk speakers were underwhelming. The DB652 received a C+ grade, tying it with two other speakers as the sixth-most efficient speaker in the test.
The power-handling specifications are excellent, with a continuous power-handling rating of 100 RMS watts and a peak power handling of 300 watts. Both are as high as it gets for a marine speaker, which means it can handle more power and reach higher volumes.
All of the Polk DB+ speakers are marine certified. This means they’ve been rigorously designed and tested to handle salt, fog, humidity, water and the sun. The speakers have ASTM certifications for salt, fog and UV rays, which is a must for boat speakers. The tweeter is made of aluminum, and the woofer is made of polypropylene. Both are noncorrosive and resistant to water.
The one durability feature missing is gold-plated terminals. Gold doesn’t rust and is one of the best conductive metals, which is critical to ensuring the speakers get as clean an audio signal as possible.
The Polk DB+ series of marine speakers is an excellent option for upgrading your boat’s sound system. Not only are these the most affordable speakers in our review, but they pack a punch. With its high power-handling, you can really turn it up with the Polk DB652. Just don’t expect the audio quality to match that of more expensive coaxial speakers, such as the Polk MM.