6x9-inch coaxial mobile audio 3-way loudspeaker

6" x 9" coaxial
15.24cm x 22.86cm coaxial


$27995 per pair

Available Finishes:
Additional Images

Designed to Perform

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!

MM691 Features:

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

Diameter3/4" (1.91cm) 
TypeSilk composite dome 
Diameter1" (2.54cm) 
TypeSilk composite done 
Mid / Woofer
Oval Height6" (15.24cm) 
Oval Width9" (22.86cm) 
TypeDynamic Balance driver with poly composite cone 


Total Frequency Response30-25kHz 
Nominal Impedance2.7 ohms
Efficiency94 dB
Power Handling
Continuous125 watts
Peak300 watts


Oval Cut-Out Height8 3/8" (21.27cm) 
Oval Cut-Out Width5 1/2" (13.97cm) 
Height1 1/8" (2.86cm) 
Full-Range Mounting Depth
Top Mount3 3/16" (8.10cm) 
Bottom Mount3 1/2" (8.89cm) 


Unit of Measurepair 


Speaker Warranty1 year parts and labor (original purchaser) 

Specifications, dimensions and features subject to change without notice. For more information call us at 1-800-377-7655 (USA and Canada). Outside of North America call +1 (410) 358-3600.

MM691 Media

MM691 Accessories