ElectroMotion ESL's XStat electrostatic MicroPerf panel is housed within a radical aluminum and composite AirFrame similar to those found on MartinLogan's flagship products. AirFrame technology rigidifies the electrostatic panel without obstructing playable surface area or interfering with ambience enriching dipole sound radiation. At the same time, an AirFrame provides electrical and acoustical isolation, minimizing intermodulated distortion caused by vibration and resonance while enhancing imaging, low-level sonic detail, accuracy, and efficiency. MicroPerf design optimizes the individual holes of The EM-ESL's electrostatic panel. MicroPerf design substantially increases diaphragm radiating area, compared to early generations, without compromising structural integrity. The resulting increase in output capability and efficiency allows The EM-ESL's panel to enjoy a substantial leap in bandwidth and dynamics without growing larger. For example, The EM-ESL's XStat electrostatic panel features 129 square inches of sound radiating surface on both the front and back and a sensitivity of 91dB into 6 Ohms. Another key attribute of the ElectroMotion ESL is its naturally dipolar radiation pattern. A true dipole, The EM-ESL radiates sound with equal intensity from the front and back of its diaphragm, but the outputs are in opposite phase. As a result, sound waves rippling out toward the sides meet at the speaker's edge and cancel. To seamlessly blend audio output from the high- and mid-frequency electrostatic panel to the low-frequency woofer, the ElectroMotion ESL features a proprietary Vojtko topology filter utilizing custom air core coil and low DCR steel laminate inductors, polyester film capacitors in series, and low DF electrolytic capacitors in parallel. A precise 8" high-excursion, perfectly balanced, audiophile grade, doped fiber cone woofer was custom designed exclusively for The EM-ESL by MartinLogan's in-house engineering team. This woofer precisely optimizes cone suspension and magnetic flux field to produce high levels of bass output and simultaneous precise midrange. The custom woofer's rigid light-weight diaphragm eliminates cone flexure and maximizes response time to achieve remarkably low-distortion approaching that of MartinLogan's award-winning electrostatic panel design. Convenient push-style speaker terminals and curved inserts help guide speaker wire effortlessly into place. The rubber end caps on the terminal are also removable for the use of banana plugs instead of bare wire. The EM-ESL is supplied with sturdy, 1/4-20 ETC spikes, which can be used to fine tune vertical wave launch, enhance stability on thick carpets, and create tighter coupling between speaker and floor to provide a tighter and detailed bass performance. Each spike is conveniently covered by removable rubber end caps if you prefer not to use spikes.