Loudspeakers

Tested with a likely partner for the LōKē, the Wilson SabrinaX [HFN Dec '20], the sheer scope of the former's low-pass (LPF) and subsonic (HPF) frequency and slope options, plus phase, output level, parametric EQ and placement scenarios enables many possible response combinations. For the sake of expediency I left the subsonic (HPF) and PEQ features disabled for the 'flattest' VLF response and focused, instead, on the tunable (30Hz-125Hz, ±1Hz) LPF options while integrating the LōKē with the SabrinaX. The latter's port has a 27Hz-85Hz range that supports the 60Hz-280Hz passband of the 203mm pulp woofer (all –6dB limits), realising a 52Hz bass extension (–6dB re. 200Hz) despite a steep LF roll-off [dashed trace, Graph 2]. However, when optimally integrated with the LōKē using a 60Hz/12dB/octave slope [black trace, Graph 2], this takes the diffraction-corrected system response down to a rib-tickling 17Hz. The impact of higher and lower LPF frequencies [80Hz, blue; 40Hz, red, Graph 2] is clear, just as the residual notch at ~50Hz may be further fine-tuned by boundary placement and steadily inverting the polarity of the LōKē's output via its 'Phase Degree' facility.

In common with most modern DSP-governed subs, the LōKē is very versatile. Increasing the LPF frequency from 40Hz in steps up to 125Hz results in a shift in the LōKē's passband from 19Hz-98Hz to 42Hz-120Hz (all re. –6dB) – working ranges that are not significantly influenced by the 12dB or 24dB/octave roll-offs [solid traces, Graph 1]. The long slot port is tuned to 22Hz with an effective 13Hz-134Hz (–6dB) output when the LPF is set to its maximum 125Hz [dashed traces, Graph 1]. The peak at 111Hz, prior to a steep roll-off, is tamed once the LPF is set to 80Hz or lower [dashed blue trace]. Ultimate bass extension is influenced by boundary reinforcement and the LPF (and subsonic HPF, if applied) but useful output below 15Hz (–6dB re. 100Hz) is perfectly achievable. There is some small penalty in 2nd harmonic distortion below 60Hz, however, where levels increase from ~0.1% to ~0.9%/50Hz and ~9%/40Hz (all re. 90dB SPL). PM