Loudspeakers

Take MoFi’s SourcePoint 8 [HFN Aug ’23], double the enclosure volume and add two additional 200mm bass units to relieve the concentric 32mm tweeter/200mm midrange of all bass duties below 130Hz and, hey presto, you’ll have the 888... Higher SPLs are possible here, deeper bass and a much reduced LF distortion (0.1% vs. 0.8% re. 100Hz/90dB/1m) while sensitivity is 1dB higher at 87.7dB/1kHz but unchanged at 86.4dB/500Hz-8kHz. However, the 888 is a tougher drive, meeting its 6ohm nominal and 4.5ohm minimum rating with a dip to just 4.5ohm at a very low 29Hz and 4.6ohm at 78Hz. The impedance modulus lies below 8ohm from 45Hz-2.3kHz, and with phase angles dropping to –66o in the deep bass there’s an EPDR of 1.7ohm/26Hz and sub-3ohm from 48-73Hz for the amplifier to deal with.

The 888’s response trend is like a mildly exaggerated ’8 – the facetted baffle is no longer symmetrical here – the coaxial treble dome now responsible for slightly higher ±4.4dB and ±5.8dB response errors [see Graph 1] and ~2dB pair matching. A smoother trend is revealed by listening slightly off-axis [grey trace] where the response is flat to within a tighter ±1.6dB (ignoring the +4dB/19kHz peak). Again, the plastic-framed grille disrupts the baffle’s facets, leading to bold peaks and notches in the presence/treble [blue trace] – remove before listening! The ports are both tuned to 31Hz and are broadly free of pipe or cabinet modes, the most obvious at 615Hz (–24dB). The two 200mm paper-coned bass drivers operate between 40Hz-160Hz (–6dB), leaving the ports to push the diffraction-correction bass extension down to a very creditable 32Hz (–6dB re. 200Hz). PM