System Audio Legend 60.2 Silverback Active Loudspeaker Lab Report

Lab Report

As Mark discusses in our review, this 'Silverback' version of the Legend 60.2 is very much more than an actively-driven version of the 'passive' 60.2. Same cabinet and same combination of four 150mm carbon-fibre reinforced bass units, except the ports in the Silverback are internally 'shorted' to yield something closer to a 2nd-order sealed-box bass alignment. In practice these foam bungs do not provide an hermetic seal, so the alignment is slightly 'leaky'. Moreover the quad woofers are separated into two pairs, each driven in parallel from one TI Class D amp and delivering a useful –6dB bandpass of 18Hz-130Hz. With Room Service correction applied [see boxout, p59] the bass is extended to circa-20Hz [–6dB re. 200Hz; green shaded area, Graph 1].

The forward response, however, shows a generally uptilted trend from bass through to treble, albeit with an upper mid/presence band depression. This was a more significant –5dB/2.1kHz dip in the 'left' speaker compared to –2.5dB in the 'right' and responsible for the below average 4.7dB pair matching [black/red traces, Graph 1] and higher ±6dB response error in the 'left'. That the mid/treble crossover is increased from 1.85kHz (passive 60.2) to a higher 3.2kHz in the 60.2 Silverback, thereby stretching the reach of the 150mm mid driver, may not be coincidental, but toeing the speakers a little off-axis certainly tempers the brightened treble.

The blend of rigidity and self-damping offered by SA's bass/mid cone material is ably illustrated by the low-level of breakup modes [CSD waterall, Graph 2]. THD, meanwhile, is a low 0.3-0.35% through bass and mid (re. 90dB SPL/1m) and principally 3rd harmonic, though this segues to 2nd harmonic at higher frequencies as the ultrasonic response is limited to ~26kHz (–6dB re. 10kHz) via the soft dome tweeter [pink shaded area, Graph 1]. (TI's 'Ultra-HD/PurePath' Class D modules will accept 96kHz digital inputs, conferring a potential ~48kHz bandwidth.) PM

621sa.lab1

Response inc. corrected nearfield <200Hz [green], freefield corrected to 1m [yellow], ultrasonic [pink]. Left speaker, black (with grille, blue); right speaker, red; ±6dB settings, grey (from 400Hz)

621sa.lab2

Low-level modes visible from the four bass units up to 2kHz and mid at 6kHz but tweeter is clean

Pair matching/Resp. error (200Hz–20kHz) 4.7dB/ ±6.1dB/±4.3dB
LF/HF extension (–6dB ref 200Hz/10kHz) 20Hz / 25.5kHz/26.7kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.35% / 0.30% / 0.50%
Dimensions (HWD) / Weight (each) 1180x200x335mm / 27kg
Price £7000 (£400 wireless stereo hub)

COMPANY INFO
System Audio A/S
Denmark
Supplied by: Karma-AV Ltd, York
01423 358846
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