MartinLogan Motion XT F200 Loudspeaker Lab Report

Lab Report

Such is the height of these loudspeakers that most owners will be listening on or below the axis of MartinLogan's proprietary 'Folded Motion' tweeter. At this position the F200s have a generally uptilted balance [see Graph 1] with ±3.7dB response errors, respectively, that are realised in a ~5dB uplift through presence and treble frequencies. Listening below or off the horizontal axis tends to 'flatten' this trend slightly while the snug-fitting grilles are superbly engineered to offer very little disruption [blue trace, Graph 1]. Both speakers show a mode associated with the minor bump in response at 800Hz (the pair matching is 0.8dB) but the F200's cumulative decay is otherwise very clean indeed [see Graph 2] with only very minor breakup modes in the pleated tweeter. Sensitivity, meanwhile, is necessarily influenced by the uptilted response, from a modest 87.0dB/1kHz to an improved 89.1dB (500Hz-8kHz) that's still short of ML's ambitious 92dB/2.83V/1m specification.

MartinLogan's 4ohm nominal rating for the F200 accurately reflects the minimum 3.6ohm/88Hz impedance. Phase angles swing from –60°/25Hz to +31°/1kHz and contribute to the min. 1.3ohm/73Hz EPDR which will demand an amplifier with good reserves of current, especially in the bass. Talking of which, the three 203mm reinforced Kevlar-coned woofers all have a narrow 50-190Hz bandwidth (–6dB) – rather tighter than the 300Hz crossover might suggest – which, with the 35Hz-tuned ports (these also with a mild quarterwave resonance) deliver a diffraction-corrected bass extension of 35Hz and a peak in output at ~70Hz [green shaded area, Graph 1]. PM


Response inc. nearfield summed driver/port [green], freefield corrected to 1m at 2.83V [yellow], ultrasonic [pink]. Left, black; right, red; w. grille, blue

MartinLogan Motion XT F200_Waterfall_L_35dB

Above 1kHz, and aside from two minor FMT modes at 7kHz and 14kHz, the F200 looks very clean

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 87.0dB / 89.1dB / 87.3dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 3.58ohm @ 87.9Hz, 39.6ohm @ 21Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –59.8° @ 24.7Hz, +31.2° @ 1.03kHz
Pair matching/Resp. error (200Hz–20kHz) 0.80dB / ±3.7dB/±3.7dB
LF/HF extension (–6dB ref 200Hz/10kHz) 35Hz / 28.5kHz/28.5kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.08% / 0.4% / 0.35%
Dimensions (HWD) / Weight (each) 1289x349x419mm / 39kg
Price £6495

Lawrence, KS, US
Supplied by: The Professional Monitor Company Ltd, UK
01767 686300