Loudspeakers

Sharing the same 28mm silk dome tweeter and similar 250mm pulp-coned bass/mid driver with the O/96 [HFN Apr '21] means there are parallels between this latter model and the lower sensitivity O/93. 'Lower' is not 'low', however, for DeVore still rates the O/93 at a high 93dB/1W/1m. With a nominal impedance of 10ohm (actually 17ohm/1kHz), this brings sensitivity closer to 92dB at the standard 2.83V/1m [see boxout, p65], a figure that's still higher than the 90.3dB/1kHz measured here. The slightly downtilted presence/lower treble [see Graph 1] drops sensitivity to 89.7dB from 500Hz-8kHz but, in practice, the O/93 only loses 1.8dB to the 96dB-rated O/96. Again, this fine sensitivity is not achieved at the expense of a punishing load as the O/93 only momentarily drops below 7ohm (155-185Hz) and, with swings in phase angle of +54°/–60° through the bass, presents the partnering amplifier with a worse-case 3.1ohm/99Hz EPDR, putting it in the top few percent of 'easy-to-drive' loudspeakers.

The 90cm-tall O/93 has been engineered to be heard on an above-cabinet axis where its response errors amount to a mere ±1.9dB (200Hz-19kHz) and pair matching a fine ±0.6dB. However, (port/cabinet) resonances are visible on the impedance/phase spectra at 190-550Hz while a driver mode at 1.9kHz, and harmonics, are visible on both the forward response and CSD waterfall [see Graph 2]. While this may contribute some 'colour', conventional distortion remains a low ~0.5% (re. 90dB SPL) through the bass and midrange, the former augmented by the 35Hz tuning of its two rear-firing ports to yield a steeply rolled-off but deep bass extension of 36Hz (–6dB re. 200Hz). PM