Loudspeakers

A four-driver, reflex-loaded three-way it may be, but the Legend 40 remains compact as floorstanders go, so even with a 4ohm nominal impedance its rated 90dB sensitivity looks very optimistic. My measurements suggest a figure some 2.5dB lower is more realistic – taken either at 1kHz/1m/2.83V or as a mean from 500Hz-8kHz. SA indicates a minimum 3ohm/140Hz impedance for the Legend 40 and this was matched on test at 2.9ohm/130Hz – this plus relatively big swings in phase angle from +40o to –63o make for a very tough load through the bass region. Weedy amplifiers need not apply... Distortion, principally 2nd harmonic, is <0.5% through bass and midrange (re. 90dB SPL/1m) while an increasing 3rd harmonic pushes this up to <1% through the treble – all worthy figures nonetheless.

Forward frequency responses measured at 1m on the tweeter axis [see Graph 1], showed a pair matching error of 2.3dB between the two cabinets due to a dishing in output from 1.3kHz-4.3kHz from one sample [red trace]. Output picks up through presence and treble with modest +2.8dB response errors, although the grille [blue trace] produces cancellation notches at 4kHz and at 13kHz. The step in response at 1.2kHz correlates with a driver breakup mode [see Graph 2] and is close to the 4th-order 2kHz mid/treble crossover. Corrected nearfield bass measurements, with no boundary reinforcement, show a similarly steep LF roll-off below 100Hz [green shaded area] – the two bass drivers peak at 117Hz and the port is tuned to a much lower 40Hz, so the modest 50Hz bass extension (–6dB re. 200Hz) will be much improved by near-wall positioning. PM