MartinLogan Motion® 4i Bo
Frequency Response | 70–23,000 Hz ±3dB |
Recommended Amplifier Power | 20—150 watts per channel |
Horizontal Dispersion | 80° |
Vertical Dispersion | 80° |
Sensitivity | 90 dB/2.83 volts/meter |
Impedance | 4 Ohms Compatible with 4, 6, or 8 Ohm rated amplifiers. |
Crossover Frequency | 2,900 Hz |
High Frequency Transducer | 1" × 1.4" (2.6cm × 3.6cm) Folded Motion Transducer with 5.25" × 1.75" (13.3cm × 4.4cm) diaphragm |
Low Frequency Transducer | 4" (10.2cm) paper cone with stamped steel basket. Non-resonant asymmetrical chamber format. Rigid structured dust cap to reduce cone break-up modes. Folded bass reflex port. |
Components | Custom air core coil and low DCR steel laminate inductors. Polyester film capacitors in series and low DF electrolytic capacitors in parallel. Overall system thermal/current protection. |
Inputs | Push style with banana jacks |
Weight | 6 lbs. (2.72 kg) |
Dimensions | 12.6" x 5.6" x 5.7 " |
Engineering, Without Compromises
What makes the Motion Series sound so amazing? MartinLogan’s dedicated in-house engineering and design team started by utilizing and refining the most advanced, compact technologies and combining them with innovative engineering and time-honored cabinet construction techniques. The result is an emotionally engaging sound that rivals (and most times trounces) traditional loudspeakers of similar size and price. Our ‘no compromise’ philosophy gives Motion Series a unique sound you won’t find anywhere else.
Sound Inspired by Electrostatic Speakers
The success of the Motion Series is directly attributed to its close relation to MartinLogan’s legendary ultra-high-end electrostatic loudspeakers. The desire to transmute that level of performance into a more traditional loudspeaker at a more affordable price drove the initial design imperatives that created the Motion Series.
Folded Motion® Tweeters
MartinLogan’s signature Folded Motion tweeter utilizes an extremely low mass diaphragm that “squeezes” air, thus demanding significantly less excursion than the typical 1-inch dome tweeter. Its folded design allows for a much larger surface area (compared to that of a regular 1-inch dome tweeter), controlled dispersion characteristics, and vanishingly low distortion. It’s a miracle of audio engineering that’s able to deliver much of the high-frequency detail and speed of a large, dynamic electrostatic panel in a small space.
Powerful Aluminum Cone Mid-Frequency and Bass Drivers
Custom built, low-distortion drivers pair high-power magnet structures with aluminum cone diaphragms to deliver massive excursion and sound output, preserve minute bass details, and maximize power handling capability, all without a hint of distortion. A unique concave dust cap design reinforces the strength and rigidity of the cone while reducing break up modes. The use of aluminum for cones maximizes rigidity and strength of the drivers without adding excessive weight. This, along with the exceptional damping properties of aluminum, ensures the smooth, non-resonant response necessary for seamless blending with high-resolution Folded Motion tweeters. An added benefit of aluminum is its outstanding thermal conduction capability which allows cones to serve as efficient heat sinks for voice coils.