Powerful compact bookshelf speaker with a Folded Motion™ tweeter and Folded Motion Cascading Bass-Reflex Port for deeper bass response.  Voice-matched with MartinLogan ESL speakers. 
 
 
Folded Motion® Tweeters  
The signature Folded Motion tweeters utilize extremely low mass diaphragms that "squeeze" air, and require significantly less excursion than the typical 1-inch dome tweeter, which drastically minimizes distortion while providing a lightning fast response time.  The increased surface area also provides a wide, yet controlled sound dispersion to create a realistic and carefully etched sound stage.  
 
 
Engineered Curves  
Flexible installation options allow table top or on-wall installation of all four speakers. The Motion 4i bookshelf speakers can also mount upside down to facilitate placement high on a wall.  
 
 
Cascading Bass Reflex Port
MartinLogan engineers were faced with a daunting task - create a compact speaker with low-end bass reproduction found in speakers much, much larger.  After many sleepless night and a myriad of prototypes, they created the Cascading Bass Reflex Port.  This brilliant solution allows a long tuned port, which is folded over itself (think of a trombone's tuning arm) to be compacted and squeezed into the Motion 4i.  The result is amazingly detailed low bass that can play at high volumes with minimum distortion - all thanks to the elegantly simple cascading fold that slows down and controls the air motion of the bass waves.