Go back a few decades, and only a handful of car audio companies made speakers designed specifically for marine applications. Now, almost every company offers coaxial or component speakers and subwoofers engineered for boats and personal watercraft. Rockford Fosgate is at the forefront of this market, with a comprehensive line of speakers, subwoofers, amplifiers, and source units built to withstand water, sun, and the vibrations associated with marine and powersports installations. In this Test Drive Review, we’ll take a closer look at one of their most popular speakers, the M1-65. Let’s check them out!
Features of the Rockford Fosgate M1-65
The M1-65 set is part of the M1 Series of speakers and subwoofers. Think of the M1 line as the marine equivalent of Rockford Fosgate’s Punch series in car audio—it sits between the M0 and M2 lines. Officially known as the M1 6.5” Color Optix™ Marine 2-way speaker set, the package includes a pair of coaxial speakers with integrated grilles, stainless steel mounting hardware, and wire pigtails for your installer. Oh yeah, there’s an installation manual with all the specifications and details, along with a cutting template in case your installer needs to create a new mounting location in the hull or roof. Lastly, there’s a Rockford Fosgate sticker—because we LOVE stickers! Always have, always will!
The M1-65 is a 6.5-inch class speaker and mounts in a 5.36-inch cutout. The outer diameter is 7.09 inches, and the mounting depth measures 2.52 inches. As noted, the grille is integrated into the speaker. While this simplifies installation, there are two main design reasons. First, the grille suspends the tweeter above the woofer, with no traditional tweeter post extending through the center of the woofer cone. This design maximized effective cone area, increasing the system’s efficiency. We’ll get to the second design reason in just a bit.
Speaker Chassis and Grille Material
The woofer uses an injection-molded Acrylonitrile Styrene Acrylate (ASA) plastic frame. This material is very similar to ABS plastic but substitutes butadiene rubber with a styrene-acrylonitrile matrix. In practical terms, ASA offers 10 times better weathering and UV resistance, improved heat resistance and reduced susceptibility to heat-related cracks. It’s a smart, albeit more costly, choice for marine-grade speaker baskets and grilles. That cost is one reason not every manufacturer uses it.
The woofer cone is molded from mineral-filled polypropylene, a material that boasts excellent UV degradation resistance. The cone is chemically bonded to a Santoprene rubber surround, which attaches to the basket using Rockford Fosgate’s proprietary Vertical Attach Surround Technique (VAST). This chemical bond strengthens the mounting point, while VAST increases cone area significantly, improving efficiency and bass extension.
A one-inch voice coil is wound on a Kapton former. This larger-than-average voice coil allows the speaker to handle 75 watts of continuous power and up to 300 watts peak. The cone and voice coil are suspended by a linear synthetic blend spider. During our inspection and photography of the driver, we observed that the tinsel leads are sewn to the spider to reduce noise and are mounted on opposite sides of the woofer for balanced compliance and linear cone movement.
The M1-65 boasts an efficiency rating of 90 dB SPL measured with one watt of power at a distance of one meter. The voice coil has a nominal impedance of 4 ohms, and the frequency response is rated from 38 Hz to 22 kHz. All specifications comply with the ANSI/CTA-2031 standard for mobile speaker specs, assuring reliability and consistency.
The tweeter is a one-inch LCP (Liquid Crystal Polymer) balanced dome design and includes both an integrated grille and a phase plug. That phase plug helps reduce frequency peaks at higher frequencies while also protecting the delicate tweeter dome—something we appreciate, especially after witnessing countless poked-in tweeters at retail shops over the years.
The tweeter is crossed overusing a single electrolytic capacitor, resulting in a 6 dB/octave slope. This component is integrated into the speaker basket and frame for cleaner installation. It’s all part of the integrated grille design.
Rockford Fosgate Color Optix Illumination
The second reason for the integrated grille design? Rockford Fosgate’s Color Optix. This is the name of their RGB LED lighting system integrated directly into the speakers. You’ll find three electrical connection sets on the back of the speaker chassis: nickel-plated solid brass speaker terminals and two Deutsch connectors—one two-pin connector for speaker wiring and one four-pin connector for the RGB LED lighting.
The optional Color Optix PMX-RGB controller can drive up to eight Rockford Fosgate speakers and uses weather-resistant cables for durability. When paired with the RF Connect app on iOS or Android devices, you can select from a wide range of illumination colors, or set the lights to flash or fade. The PMX-RGB is required for complete color control. Otherwise, the included Deutsch pigtails can select a static color.
You’ll find a wide range of Color Optix accessories, including Y-adaptors and extension cables, at www.rockfordfosgate.com/products/details/m1-65.
All RGB LED wiring is built into the speaker basket, so your installer only needs to connect and mount the speakers to get up and running. Every Color Optix feature, including the RGB diffuser ring, uses UV-stable plastics like the frame and grille.
To explain how the Color Optix works, a small circuit board (just larger than the tweeter) is mounted behind the grille. The board features several RGB LEDs that light up the woofer cone with your selected color.
Element Ready Design
We’ve already discussed UV stability extensively, but Rockford Fosgate’s Element Ready approach takes durability to the next level. The M1-65 speakers are rated IPX6 for water intrusion and feature a rubber gasket to ensure a seal when mounted against a boat’s hull or roof. To guard against saltwater corrosion, the speakers pass ASTM B117 salt fog testing. Ultraviolet resistance is confirmed through 500-hour ASTM-G154 UV exposure testing to ensure components don’t fade, yellow, chalk, or dry out.
Unlike many lesser designs, Rockford Fosgate subjects its Element Ready products to rigorous vibration and impact testing to ensure every part remains securely in place. This testing complies with ISO 60068-2-64 standards.
We’ve said this about every Rockford Fosgate product we’ve had the pleasure to review—you might find something cheaper that looks similar, but you won’t find the same level of thoughtful design, quality, and performance. That’s not marketing spin—it’s based on hands-on testing of more than 20 Rockford Fosgate products over the years. Rockford stands behind the M1-65 with a two-year warranty against manufacturing defects.
Listening Audition
Before placing the M1-65s in our test enclosures, we exercised the suspension by feeding the speakers a 38 Hz sine wave for 8 hours. This helps break in the spider and surround. We captured Thiele-Small parameter measurements using our Clio Pocket system, as it allows for in-circuit evaluation even with the tweeter non-removable.
Our first track was “One” by Metallica, and the tweeter’s forward tuning became evident immediately. The upper guitar tones and stick strikes were lively and detailed. Floor toms came through well, more so than the kick drum.
We followed that up with “Give Life Back to Music” by Daft Punk, which had a much stronger bass presence. Vocals were clear, smooth, and not at all sibilant. Again, the tweeter’s output gave the song a vivid presence without straying into harshness.
Next up was “Yellow Flicker Beat” by Lorde—a go-to reference track for vocal texture and detail. Ella’s enunciation on “S” and “T” sounds was pronounced but not excessive. The warm bass line at 1:04 worked well to balance the top-end presence.
Finally, we auditioned “Your Latest Trick” by Dire Straits. The tweeter’s upper-frequency output helped make the horns and percussion stand out with impressive clarity. Mark Knopfler’s lower-register vocals were well-reproduced and smooth.
Marine speakers like the M1-65 are purpose-designed, emphasizing the upper frequencies, which helps project sound over wind and water noise. These speakers are not midbass-focused, and that’s intentional. The lighter cone and spider assemblies maximize efficiency, reducing power demands. All around, Rockford Fosgate got the balance right for marine and powersports use.
Lab Measurements
After the listening session, we returned to lab testing for Thiele-Small measurements. The resonant frequency decreased from 80.6 Hz to 71.8 Hz after break-in, and compliance rose from 7.7 to 8.4 liters. Efficiency dropped slightly—about 1 dB—after suspension exercise.
The predicted frequency response is smooth. Instead of an exaggerated midbass hump, the design maintains consistent response down to just above 100 Hz—an efficient approach that suits lower-power head unit applications. If you want to extract full potential, Rockford Fosgate’s M2-300X4 amplifier is a perfect match.
You might notice a discrepancy between the predicted woofer efficiency (86.53 dB SPL) and the rated 90 dB efficiency—this difference is likely due to the added output of the tweeter. We’re confident that the published number is accurate.
The impedance curve displays two resonance ripples at 1.1 and 2.25 kHz, likely cone or dust cap-related. Outside of that, the curve is smooth. Notably, impedance remains very close to 4 ohms at high frequencies—a trait that helps Class-D amplifiers perform optimally.
Conclusions on the Rockford Fosgate M1-65 Speaker Set
A lot more goes into a great marine speaker than just making it white. Rockford Fosgate’s engineering team has packed innovative features and smart materials into the M1-65, creating a speaker that delivers impressive performance—whether you’re dockside or skimming waves at full throttle. These same benefits also make the M1-65 an excellent choice for powersports vehicles like side-by-sides. In fact, they’re part of the Stage 3 and Stage 4 audio upgrades for Rockford Fosgate’s RZR and Can-Am X3 kits.
If you’re in the market for premium marine or powersports speakers, drop by your local authorized Rockford Fosgate retailer to audition the M1-65 set. They’re available in 6.5- and 8-inch models, with your choice of black or white frames and grilles.
Need help finding a retailer? Use the Rockford Fosgate Dealer Locator. Don’t forget to follow the team from Tempe, AZ, on Facebook, Instagram, and YouTube to stay up to date on new products and events.
