Loudspeakers

JBL is very realistic in its specifications for the Summit Makalu. For example, the rated 88dB sensitivity is met at 88.0dB (re. 1kHz/2.83V/1m) and 87.6dB (500Hz-8kHz) while the 4ohm nominal impedance and 3.4ohm/79Hz minimum was precisely matched on test, the substantive +59°/–69° swings in phase angle dropping the minimum EPDR to 1.25ohm/63Hz, remaining sub-5ohm from 45-2kHz. Bass is usefully extended, and with low 0.1% distortion (re. 90dB SPL/1m), the 300mm woofer operating between 44-250Hz (–6dB), peaking at 60Hz, and supplemented by the broad 35Hz port tuning to deliver 29Hz (–6dB re. 200Hz). In short, the Makalu blends modest sensitivity, good extension with tough but not 'evil' amplifier loading.

Measured at the lower lip of the horn, the forward response is remarkably flat and even with errors of just ±1.7dB (200Hz-10kHz) increasing to ±2.6dB and ±2.9dB, respectively, once the larger variations between 10-20kHz are included [Graph 1]. The dip at 620Hz is a baffle step effect while, at the far end of the scale, the new 75mm annular ring driver's main breakup is deferred to a very respectable 27kHz [pink shaded area, Graph 1 and CSD waterfall, Graph 2]. The 33kHz extension (–6dB re. 10kHz) is also bang-on JBL's spec. Off-axis [blue trace, Graph 1], the midband is flatter still, traded for a loss in HF output above 10kHz (–11dB/20kHz) – careful toe-out will enable fine-tuning of the Makalu's far treble 'bite'. Pair matching amounted to 0.7dB with the biggest variation occurring through the 1.1kHz crossover [black/red traces] while the snug-fitting plastic framed grille exerts little or no impact on response [grey trace]. PM