Article Index
Martin Logan Electromotion review
Page 2
Sound Quality
Measured Performance
All Pages


Martin Logan’s electrostatic panel gives an even output from 400Hz to 18kHz, free from major peaks or dips, when measured on-axis. There is a small plateau lift in output around 1.5kHz and this will give the speaker a little extra presence. With electrostatics though this is usually less obvous and unpleasent than with other loudspeakers. Off axis the result was similar, except upper treble above 5kHz starts to fall away. The best result was just slightly off-axis by a few degrees so the loudspeakers can be pointed straight down a room, rather toed-in to point directly at listeners.


Output from the bass unit was in good balance with the electrostatic panel, the downward firing port taking over from the bass unit below 80Hz. It works smoothly down to 25Hz our red trace shows, imposing good acoustic damping upon the bass unit, seen both in the breadth of its acoustic output and in the wide dip around 36Hz in the impedance curve. Bass quality should be good and deep bass apparent at times.


As electrostatics go, sensitivity was high, measuring 87dB from one nominal watt (2.8V) of input. The ElectroMotion doesn’t need lots of power to go loud and around 60 Watts should be enough for most rooms. Our impedance curve shows impedance sinks to 1 Ohm at 20kHz, as it does with most electrostatics, and not all transistor amplifiers will be happy about this if strong treble exists in a recording and volume is high. Impedance measured 5.3 Ohms overall however, largely because the bass unit has a 4.7 Ohm D.C. resistance.


As expected an analysis of the loudspeaker’s decay spectrum over 200mS showed a very clean result, as expected from an electrostatic panel with no surrounding cabinet. Even the bass bin looked clean, in spite of small cabinet size. Bass distortion was very low at less than 1%, apart from a small peak around 40Hz where it reached 4%. The profiled port was unusually linear too, with just 4% distortion at 40Hz. The electrostatic panel also measured well over its operating range with distortion typically 0.1%, much lower than cone loudspeakers.


The ElectroMotion measured well in all areas. The bass cabinet in particular looks stronger than previous designs, better damped and likely less boomy as a result. NK


FREQUENCY RESPONSE (what it means)


Green - drive unit; Red - port


IMPEDANCE (what it means)



DECAY SPECTRUM 200mS (what it means)


DECAY MAP 200mS (what it means)


DISTORTION (what it means)



BASS DISTORTION (what it means)




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