Loudspeakers

A typical seated height will likely place the listener on the axis of the 25mm ‘Diamond’ tweeter where the Parker Trio shows a gently dished ‘BBC-esque’ forward response, with a fulsome bass but milder mid/presence [see Graph 1]. The tweeter is wired in reverse-phase to aid integration with the adjacent 190mm ceramic bass/mid driver, the latter operating over an extended 43Hz-1.7kHz (–6dB) bandwidth. The lower ‘true woofer’ occupies 43Hz-450Hz (–6dB re. 100Hz) while the rear-firing, alloy ABRs are tuned to 32Hz, the ensemble delivering a very respectable diffraction-corrected bass extension of 35Hz (–6dB re. 200Hz).

A peak in response at the 2.2kHz crossover followed by a ~6dB dip at 3.3kHz largely accounts for the ±4.6dB response errors (200Hz-20kHz) and correlates with mild driver modes visible on the CSD waterfall [see Graph 2]. Our speakers were tightly matched – within 0.4dB (200Hz-20kHz) – deviating only above 20kHz [red/black traces, Graph 1]. The Diamond tweeter has a very extended 73kHz range (–6dB re. 10kHz) but there are modes at 35kHz, 48kHz and 58kHz just as likely caused by an interaction with the metal grille. Toeing the speakers away from the listening axis by just ±15° delivers a flatter top-end response that dips quite sharply above 33kHz [grey trace, Graph 1].

Marten’s 91dB sensitivity rating is too optimistic – 87.3dB/1kHz and 86.1dB/500Hz-8kHz are achieved in practice, while the 3.3ohm/159Hz minimum impedance suggests a nominal 4ohm rather than 6ohm. The biggest swings in impedance phase occur below 100Hz and at the HF crossover, leading to two quite tough EPDRs of 1.54ohm/85Hz and 1.49ohm/2.15kHz. PM