Whether you’re into four-wheeling, two-wheeling, hot-rodding, or just a leisurely drive, you’ll find no better way to enjoy your music on the road, or off, than with our db, DXi or MM loudspeakers and component systems. These series continue to be the performance standard and all offer the kind of styling that can work in a big-block American classic or a high-tech import.

MM691 6x9” 3-Way Coaxial Speakers

6x9-inch coaxial mobile audio 3-way loudspeaker

The MM691 is an ultra-high performance 3-way 6x9-inch suitable for either your vehicle or boat. 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. The MM Series offers exceptional value for the price. Through the use of high-tech carbon 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. In addition, these space age materials offer weight savings that can mean higher performance for your car or boat. You won’t be disappointed with the MM691’s performance!

RRP $289.00 AUD

Product Manual

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.

Large-diameter voice coils (30mm) in drivers increase reliability and power handling capacity.

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. Correct Craft offers Polk speakers in their award-winning Nautiques ski and wakeboarding boats.

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.

Driver Complement

Diameter 3/4" (1.91cm) 
Type Silk composite dome 
Diameter 1" (2.54cm) 
Type Silk composite done 
Mid / Woofer
Oval Height 6" (15.24cm) 
Oval Width 9" (22.86cm) 
Type Dynamic Balance driver with poly composite cone 


Total Frequency Response 30-25kHz 
Nominal Impedance 2.7 ohms
Efficiency 94 dB
Power Handling
Continuous 125 watts
Peak 300 watts


Unit of Measure pair 


Oval Height 8 3/8" (21.27cm) 
Oval Width 5 1/2" (13.97cm) 
Full-Range Mounting Depth
Top Mount 3 3/16" (8.10cm) 
Bottom Mount 3 1/2" (8.89cm) 
Height 1 1/8" (2.86cm) 


Speaker Warranty 1 year parts and labor (original purchaser)