Loudspeakers

The Amati's 220mm woofers [inset] have been comprehensively refined for this 5th-generation model although they remain aesthetically similar to those fitted to earlier Amati designs, including the 4th-generation Amati Tradition [HFN Oct '17]. The brand's rear-facing 'Stealth Ultraflex' bass loading has also been tried-and-tested from as way back as the Lilium [HFN Jun '15] and is implemented here, via two shaped alloy slots, exiting through the speaker's spine. Reflex-loaded speakers are 'tuned' by a combination of the mass of air in the port tube and the compliance of the air in the cabinet delivering a desired Helmholtz resonance. Below this resonance frequency there's a 4th-order (24dB/oct) roll-off in the combined driver/port output but the technique typically offers an increased sensitivity and reduced distortion over an 'equivalent' sealed box design.

It's not all plain sailing, however, because turbulent airflow within the port can create distortions of its own – hence why so many current loudspeakers employ 'aerofoil' ports of one form or another – just as tube modes (resonances) can occur within the port itself, depending on its length. Sonus faber's Stealth Ultraflex system is dubbed a 'para-aperiodic interpretation of the tuned load' which claims a reduction in cabinet volume and 'elimination of spurious wind noises'. Has Sonus faber been successful? See our Lab Report, p45. PM