SL3

About the SL3

The Martin Logan SL3 is a hybrid electrostatic loudspeaker system combining a 48-inch curvilinear electrostatic midrange/high-frequency transducer with a 10-inch high-excursion cone woofer housed in a sealed-box enclosure. The electrostatic panel is curved in a 30-degree arc to increase dispersion to about 30 degrees horizontally, addressing the typical narrow dispersion of electrostatic speakers. The crossover frequency is set at 250 Hz with a 12 dB/octave slope, ensuring smooth integration between the woofer and the electrostatic panel. The speaker has a frequency response of 30 Hz to 22 kHz ±3 dB, a sensitivity of 89 dB/2.83 V/m, and a nominal impedance of 4 ohms (minimum 1.5 ohms at 20 kHz), requiring a powerful amplifier (recommended 80 to 200 watts). The cabinet is finished with hand-selected hardwood trim and a matte finish, measuring 64 inches tall, 13 inches wide, and 14 inches deep, and weighing 65 pounds each. The SL3 features bi-wireable five-way binding posts and a rear bass control switch that reduces bass output by 3 dB from 40 to 150 Hz. The design emphasizes durability, reliability, and aesthetic elegance, with a sealed woofer enclosure that improves bass definition and a conformally coated electrostatic panel for safety and performance. The SL3 was considered a reference standard for its precision and practicality and is no longer manufactured.